Central Road Research Institute, New Delhi

2011

Design of Advanced

Public Transportation

Systems Seminar Report

Ashutosh Arun

QHS-Trainee

AA

QHS-Trainee

AA

AA 2010 02

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Design of Advanced Public Transport

System- Seminar Report

Ashutosh Arun

QHS Trainee

Central Road Research Institute- New Delhi

EXECUTIVE SUMMARY

This report is an attempt to understand the implementation of various APTS technologies in vogue in

the various cities of the world in the light of average Indian traffic conditions, with special emphasis

on the Bus Transit Operations.

Advanced Public Transportation Systems are a collection of information technology and software

applications along with essential physical systems viz. Geospatial Technologies (GIS, GPS etc.),

Automatic Vehicle Location, Advanced Communications, Transport Operations Software etc. These

technologies are applicable to almost all of the Public Transportation systems including Intermediate

Para Transit which currently ply on the urban roads in different parts of the world.

APTS have been widely adopted around the world and, with special importance to Bus Transit

Operations, been widely integrated into the Bus Rapid Transit (BRT) Systems of various cities, albeit

with varying rates of success. In India, an example of a BRT system utilizing some of these

technologies is the Janmarg in Ahmedabad, Gujarat.

This report focuses on the special issue of developing a general framework for simulation models for

designing APTS for Tier I and Tier II cities of India. Major inputs required for such models have been

discussed in detail.

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OBJECTIVE

The objective of this report is to discuss in some detail the broad categories of inputs required for

developing simulation models which can be used for designing Transportation System for a Tier I or

Tier II Indian city integrating Advanced Public Transportation Systems.

Since it is a report developed for the seminar work as a part of the M. Tech. course of the author, it

would be highly appreciated of the reader to bear in mind the fact that it is a general overview of the

topics being considered and that the reader shall not expect to find very detailed technical

information. However, the list of references has been included for the benefit of the reader.

INTRODUCTION

Advanced Public Transportation Systems (APTS) are the implementation of technology

(communication, computer etc.) in the transportation sector to increase the efficiency and safety of

public transportation systems. An added benefit sought to be provided is to offer users greater access

to information on transportation system operations.

The implementation of APTS technologies is transforming the way public transportation systems

operate, and changing the nature of the transportation services that can be offered by public

transportation systems. The goal is to provide public transportation decision-makers more information

to make effective decisions on systems and operations and to increase travellers’ convenience and

ridership. Also, it aims to equip the users with greater pertinent and updated information regarding the

system and hence empower them to make smarter decisions in their choices.

APTS technologies can be organized into five broad categories that describe the technologies'

relevance to transit applications. Each category is comprised of a variety of technology choices that

are available to help transit agencies and organizations meet travellers’ service needs while increasing

safety and efficiency.

The five APTS technology categories are:

Transit Applications APTS Technologies

Fleet Management Systems Automatic Vehicle Location Systems

Transit Operations Software

Communication Systems

Geographic Information Systems

Automatic Passenger Counters

Traffic Signal Priority Systems

Traveler Information Systems Pre-Trip Transit and Multimodal Traveler

Information Systems

In-Terminal/Wayside Transit Information Systems

In-Vehicle Transit Information Systems

Electronic Payment Systems Smart Cards

Fare Distribution Systems

Clearinghouse

Transportation Demand Management Dynamic Ridesharing

Automatic Vehicle Coordination

Transportation Management Centers

Intelligent Vehicle Initiative Longitudinal Collision Avoidance

Lateral Collision Avoidance

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CHAPTER 1: APTS TECHNOLOGIES- A REVIEW

FLEET MANAGEMENT SYSTEMS

Real-time management of bus and subway systems is now possible through the use of vehicle-based

fleet management systems. Advanced Public Transportation Systems (APTS) Fleet Management

systems present transit agencies with more effective tools for vehicle and fleet planning, scheduling,

operations, control of traffic signals, and monitoring of vehicle location. Following benefits can be

obtained through the use of these technologies:

Increased ridership, as scheduling of vehicles is better aligned with demand;

Decreased costs, congestion, and pollution, as ridership increases and fewer people drive

alone;

Increased safety in transit service as technology connects the system more quickly to

emergency services;

Provide a higher level of service to riders; and

Reduce ―bunching‖ of buses on a single route.

According to Federal Transit Administration (FTA), there are six technologies falling under the

category of Fleet Management Systems:

1. Automatic Vehicle Location Systems - An AVL system is a computer-based vehicle

tracking system that includes a specific location technology (or technologies) and a method of

transmitting the data from the vehicle to a dispatch center. The location technologies found on

AVL systems are usually one of the following, but can also be used in combination:

Global Positioning System (GPS) - A network of satellites in orbit transmits signals to the

ground. Special receivers on each vehicle read the signals available to them and

triangulate to determine location.

Ground-Based Radio (e.g. Loran C) - Network of radio towers on the ground transmits

signals. Special receivers on each vehicle read the signals available to them and

triangulate to determine location.

Dead Reckoning - The vehicle uses its own odometer and a compass to measure its new

position from its old (known) position. It is often supplemented by ―map-matching‖ -

comparing expected position with a computerized map, and adjusting measured position

if the vehicle is not on a road. It is also often supplemented with readings from another

location technology, like GPS.

2. Transit Operations Software - Computer-Aided Dispatching (CAD) combined with some

form of AVL gives transit properties the capability to monitor, supervise, and control

operations with real-time data. More agencies are finding ways to use information from

AVL/CAD software packages for other purposes such as customer information, planning, and

scheduling.

CAD fixed route software falls into four primary categories, which are described in detail

below:

Transfer connection protection software- Transfer Connection Protection (TCP) software

allows bus operators to inform on-board passengers whether they will be able to make a

transfer to a connecting bus given current schedule adherence.

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Expert systems for service restoration- Using real-time bus

operations information from AVL/CAD systems and the

existing operation rules and procedures, these expert

systems aim at providing optimum solution for restoration

of disrupted service.

Itinerary planning systems- Its function is to determine the

best way for a transit customer to travel from an origin to a

destination. Itinerary planning systems are indirectly

linked to CAD systems because they depend on the same

static route schedule data.

Service planning applications- Service planning

applications are used to analyze the efficiency of fixed-

route operations using data from AVL/CAD systems.

Service planning applications can perform the following

functions:

o Provide an average of running time between time

points to determine which route segments are not

performing to schedule, by how much, and why;

o Calculate measures of headway and running time variability to determine where

service and scheduling should be adjusted for efficiency and as a measure of

customer service;

o Develop new performance measures on an as-needed basis; and

o Map the analysis for visual evaluation based on geographical referencing.

3. Communications Systems - They are used to transmit voice and data between vehicles and

operations centers, and to transmit commands between operators and technologies (e.g.,

signal pre-emption commands to traffic signal systems). The two-way voice radio system

used for fleet management and vehicle dispatching remains at the heart of most transit

operations. However, other communication technologies are becoming common; for example,

communications-based train control and short-range data links for traffic signal priority. For

bus transit operations, two types of communication technologies are used:

Mobile Voice and Data Communications Systems- It involves the broadcast of

information over Radio Frequency (RF) waves from a transmitter to receiver.

Short-Range and Other Communications- Communications systems, such as microwave,

Cellular Digital Packet Data, infrared, sonic, radio frequency, and fiber optic lines, are

excellent ways to transfer data and voice communications where long-range wireless

media are not suitable for one reason or another. E.g. Traffic Signal Priority Systems.

4. Geographic Information Systems- GIS provides a current, spatial, interactive visual

representation of transit operations. It is a type of computerized database management system

in which geographic databases are related to one another via a common set of location

coordinates. This allows users to make queries and selections of database records based on

geographic proximity and attributes. It is most often used for:

Transportation planning and modeling;

Demographic analysis;

Route planning, analysis, and restructuring;

Bus dispatch and scheduling;

Bus stop and facility inventory;

Ridership analysis;

Figure 1- Input Screen of an

Itinerary Planning Program

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Automatic vehicle location and tracking;

Fixed guideway facility management;

Paratransit scheduling and routing; and

Accident reporting and analysis.

State of California’s integration of APC (Automatic Passenger Counters), MDT (Mobile

Data Terminals) and AVL subsystems into a Web-based public information system is a good

example of this technology.

5. Automatic Passenger Counters- APCs typically use one of two counting technologies,

either treadle mats or infrared beams. Treadle mats, placed on the steps of the bus, register

passengers as they step on a mat and infrared beams (mounted either horizontally or

vertically), directed across the path of boarding and alighting passengers, register riders when

they break the beam.

6. Traffic Signal Priority Systems- Traffic signal priority is a strategy by which a particular set

of vehicles is given preference at traffic signals, either anytime they arrive at the intersection

or only under certain conditions (e.g., on-time status, amount of traffic at opposing

approaches).

To activate traffic signal priority for buses, a signal (via a sonic or optical pulse) is

transmitted from the bus to the traffic signal controller. Depending upon the phase the traffic

signal is in; the controller will either extend the current green phase or advance the timing of

the next green phase.

Figure 2- Traffic Signal Priority Method

When used in combination, as illustrated in Figure 3, they form fleet management systems that help

transit agencies improve the efficiency and safety of transit service.

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Figure 3- Complete Fleet Management System

TRAVELLER INFORMATION SYSTEMS

APTS can provide travelers with more information in more different ways than ever before. Transit

information can be of a static nature such as route maps, schedules, and fares, or dynamic information

such as route delays and real-time arrival estimates. It can include continuously updated freeway and

arterial traffic flow conditions. All data is integrated into an automated, cohesive traveler information

database that can be accessed by travelers through Web sites and kiosks as well as e-mail alerts,

television/radio broadcasts, automated telephone systems, hand-held computing devices/mobile

phones, and variable message signs.

There are three categories of these systems:-

1. Pre-Trip Transit and Multimodal Traveler

Information Systems- Pre-trip traveler information

systems help travelers make decisions about the choice

of transportation mode, route, and departure time before

they begin their trip. There are four main types of pre-

trip information: General Service Information, Itinerary

Planning, Real-Time Information, and Multimodal

Traveler Information.

2. In-Terminal/Wayside Transit Information Systems-

Many successful methods of providing transit

information, such as posting up-to-date schedules in

stations and at stops, rely on the fixed schedules of the

operators and do not include real-time updates. Waiting

transit passengers experience anxiety when there is a

delay and there is no information about the expected

Figure 4- Werb-based service for real-time information on buses

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duration of the delay or no reassurance that the expected vehicle is still on its way.

Agencies with AVL systems are able to provide real-time in-terminal or wayside transit

information. The primary devices for in-terminal and wayside systems are:

Video monitors for large amount of information and where flexibility in using graphics,

fonts, and color is needed. For example, a video monitor would be well-suited for a

display at the entrance to a station indicating which berth buses serving specific routes are

located.

Variable message signs for a relatively small

amount of information to be displayed at a

considerable distance from transit users, such as the

centralized real-time display. Also, they are

resistant to vandalism and can be used at bus stops.

These may be supplemented with audio announcements

of the displayed information. Real-time in-terminal and wayside information systems require

a communications link to a central computer system that provides the information about

upcoming arrivals.

3. In-Vehicle Transit Information Systems- In-vehicle transit information systems provide

useful en route information to travelers about their transit trips. Automated annunciation

systems relieve the vehicle operator of that responsibility by announcing stops, transfer

possibilities, and points of interest automatically, based on the vehicle's location, route, and

direction of travel. In some instances, this information is also provided to passengers via

variable message signs placed at one or more locations in the bus. Route specific software

provides the information to be dispensed. The precise information to be announced and

displayed at a particular time is determined by the agency’s AVL system.

ELECTRONIC PAYMENT SYSTEMS

Transit operators continuously look for ways to lower the

operational costs of their fare collection systems. Operators are

also interested in increasing revenue and customer convenience.

With these goals in mind, transit operators are capitalizing on the

increased automation, security and data capabilities offered by

new fare and data technologies that can be integrated into existing

fare collection systems. These systems combine fare media, such

as magnetic stripe cards or smart cards, with electronic

communications systems, data processing computers, and data

storage systems to more efficiently collect fares and may also

increase revenue by increasing ridership.

The flexibility offered by the use of smart card systems, permits

operators to more easily implement changes in fare policy by

uploading fare changes and multiple fare structures electronically

to the system payment and sales devices.

Figure 5- Public Information System using VMS

Figure 6- A passenger using Smart Card for fare payment

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The main components of systems using smart card based technology are:

A fare payment system - the infrastructure used to receive value from the fare payment

media and/or check the validity of the media for the current transit trip;

A fare distribution system - the infrastructure used for the distribution of the payment

media, as well as the distribution of the value that is loaded onto the fare media; and

Clearinghouse and back office processing systems - infrastructure used to capture and

process transaction data generated by the fare payment and distribution systems.

TRANSPORTATION DEMAND MANAGEMENT

Transportation Demand Management (TDM) is a term applied to a broad range of strategies that are

intended to change traveler behavior for the purpose of reducing or reshaping use of the transportation

system. TDM strategies employ ITS technologies to:

Facilitate and increase the use of public transportation, including carpooling, vanpooling,

walking, bicycling, and telecommuting;

Compress work weeks;

Apply congestion pricing programs; and

Manage parking and apply demand pricing.

Three TDM strategies that utilize ITS technologies are discussed in this chapter:

1. Dynamic Ridesharing — Dynamic

ridesharing (also called real-time

ridesharing) is a form of car/ vanpooling

that provides rides for occasional trips.

Dynamic ridesharing can be either a

program organized and run by an official

agency, or a system informally operated by

participants (casual carpooling). The

emphasis should be on organized programs

since only these use ITS technologies for

matching riders with drivers.

2. Automated Service Coordination —It

can be defined as multiple transportation

operators in a region that provide

coordinated service with the assistance of

APTS technologies. By coordinating the

services of multiple transportation

operators in a region, the connectivity of

public transportation services can be

greatly improved for persons who would have to travel on more than one transportation

agency’s vehicles. This will produce the opportunity for attracting more trips to public

transportation.

3. Transportation Management Centers —TMC is a term that refers to a variety of state-of-

the-art facilities in which transportation professionals can monitor, manage, or control transit

and/or traffic operations. The use of ITS technologies and services allows for real-time

management of public transit and/or traffic resources and capacity. The key ITS technologies

Figure 7- Carpooling Software

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within TMCs are communications systems, surveillance and detection systems, and

management and control systems. These systems incorporate technologies such as:

Closed Circuit Television (CCTV) cameras and loop detectors to capture information on

traffic conditions and incidents on highways and at major intersections.

AVL-equipped transit vehicles to act as traffic probes and provide valuable information on

traffic flow to the TMC, especially on roadways not usually monitored by the TMC.

Traffic signal control systems which allow for emergency and transit pre-emption/priority

as a means of improving safety, and regulating the flow of traffic, and better utilizing

capacity.

Figure 8- Transportation Management through Video Imaging

INTELLIGENT VEHICLE INITIATIVE

IVI technologies reduce the probability of motor vehicle accidents through the use of vehicle controls and driver warnings. The transit IVI platform provides an opportunity for evaluation of technologies

that improve the efficiency of the fleet and provide more safety:

Tight maneuvering/precise docking- Tight maneuvering/precise docking technologies,

using precision control and automated guidance technologies, allow the driver to handle the

bus more effectively in close quarters (terminals and tunnels). It also permits safer boarding

and alighting.

Precision control and automated guidance.

Longitudinal and lateral vehicle control for driver assistance on transit buses.

Obstacle/pedestrian detection. Obstacle/pedestrian detection technologies will warn drivers

of approaching activity in sufficient time to avoid an accident.

Fully automated overnight maintenance. Automation of bus movements through the

service areas in bus maintenance garages is another potential IVI application that is of interest

to transit operators.

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CHAPTER 2: MODEL REQUIREMENTS FOR APTS SIMULATION

In order to simulate APTS applications in bus transit, it is necessary to represent bus transit operations

at a level of detail that supports the operational characteristics of the technology or system of interest.

For example, AVL/CAD systems that monitor bus performance and determine holding and

dispatching solutions to schedule deviations cannot be simulated in a model that does not represent

the bus transit schedule. The purpose of this chapter, then, is to summarize the requirements for a

microscopic traffic and transit simulation model to be able to simulate APTS.

At the core of a good microscopic traffic simulator are sophisticated driver and traveler behavioral

models that capture the complex interactions between vehicles and between vehicles and traffic

control and information systems. Similarly, APTS simulation should be based on a detailed, veritable

representation of bus transit operations.

The following are identified as fundamental requirements of a microscopic simulator:

1. TRANSIT SYSTEM REPRESENTATION: Transit system representation refers broadly to

the system level components of bus transit operations that are generally under the control of

the transit service provider.

2. TRANSIT VEHICLE MOVEMENT AND INTERACTIONS: Transit vehicle movement

and interactions includes the microscopic vehicle operator-controlled movements of

individual vehicles along their routes, such as acceleration, lane-changing, and door opening

and closing, as well as the behaviors of other vehicles in the presence of buses.

3. DEMAND REPRESENTATION: Demand representation refers to the passengers, or

customers, and their behaviors with regard to use of the system, including en route and pre-

trip mode and route choice, as well as behavior at bus stops, such as boarding, alighting and

crowding.

4. APTS REPRESENTATION: APTS representation involves the representation of

surveillance and monitoring systems that generate and distribute real-time information, the

application of that data to real-time control strategies, and the provision of information to

travelers.

5. MEASURES OF EFFECTIVENESS: Measures of effectiveness include the indicators,

levels of service and other measures of performance that are used to evaluate the performance

of an APTS strategy.

Following is a diagram of the various APTS strategies discussed in Chapter 1 and the implications

they have with respect to bus transit operations and operations simulation.

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In the diagram, the interactions between the model requirements can be seen, where the APTS enable

a variety of real-time operational strategies (e.g. holding and dispatching) that directly affect transit

vehicle movements, provide valuable input to planning applications that lead to better transit system

design (e.g. improved scheduling and route planning), and allow the sharing of real-time performance

information with travelers to influence demand and improve passenger level of service (e.g. route

choice).

The transport system variables that are more or less constant, such as routes, schedules and passenger

demand, are products of operations planning or passenger trip planning applications and best

simulated by way of input to the model. While, APTS that interact with real-time operations and that

provide real-time information to passengers can be represented within the simulation using models

that capture interactions

Between transport vehicles and other modes.

Between transport vehicles and passengers.

Between transport vehicles and field-installed control devices.

Between transport vehicle operators and the TMC.

Between passengers and traveler information.

Figure 9- APTS impacts on transit operations and implications for simulation

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TRANSPORT SYSTEM REPRESENTATION

The transport system representation as an APTS modeling requirement can be divided into three parts:

Transport network

Schedule design

Fleet Assignment

Transport Network

The representation of the transport network includes the links, or paths, in the network that make up

bus routes, the designs and locations of bus stops along those routes, and the designs and locations of

other bus transit facilities, such as bus lanes, in the network.

This representation is critical to the interaction between the transit service and the passengers and the

surrounding traffic environment. For example, mixed traffic, as opposed to bus lane, transit routes

involve complex interactions between different modes. Bus stop design elements (e.g. single vs.

multiple berth stops) can have considerable impacts on vehicle operations at stops. Also, bus stops

that are located in the general traffic lane, as opposed to those that are removed in a wayside bay, will

require different bus operator maneuvers and stimulate different behaviors from other drivers in the

network.

The transport network may be subdivided into three levels of representation:

System-wide

Route segment level

Bus stop level

Bus operations at the bus stop-level are uniquely separate from, but not independent of, route

segment-level operations. Passenger waiting times, bus dwell times, and boarding, alighting and

crowding phenomena occur at the bus stop level. The composite effects of dwell times at a series of

stops, traffic congestion and intersection delays, in turn, may be observed at the route segment level.

Schedule Design

The schedule design determines how and when buses serve the transport network. It depends upon

various types of bus services, such as bus rapid transit, fixed route services and demand responsive

services. Pine (1998) identifies three components of the transit schedule:

Route structure

Service frequencies

Service timing

Route structure refers to where the bus travels in the performance of its assigned trips and relates to

the transit network representation. However, service frequency refers to how often a bus passes a

given stop on the route, and service timing refers to when a bus arrives at a particular location on the

route.

Fleet Assignment

A vehicle assignment is defined as the work assignment given to a single transit vehicle for the

duration of a service workday. In the context of simulation, however, it may be considered the total

work assignment given to a transit vehicle for the course of the simulation.

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For networks where the whole of a bus route is modeled, the work assignment might involve multiple

roundtrips on the route. Furthermore, the work assignments including trips where a single vehicle

serves more than one route, as is done in practice, can also be modeled.

TRANSIT VEHICLE MOVEMENT AND INTERACTIONS It refers to bus operator behavior and the behavior of other drivers in the proximity of buses.

When and how frequently buses arrive at specific locations along the route is a function of the

schedule and also susceptible to various random disturbances. These random variables include the

prevailing traffic conditions on and adjacent to the route (i.e. congestion), traffic control and

passenger demand (i.e. boarding and alighting passengers determine dwell time).

This interaction between the vehicle (bus in our case) and its environment can be taken up in two

parts: behavior between stops and behavior at and near stops.

Behavior between stops

The vehicle’s path is decided by the route structure, but the operator determines the more microscopic

movements along the predefined route, such as lane changes and accelerations.

Driving behavioral modeling is dominated by acceleration and lane-changing models, which are

typically complemented by more detailed models of gap acceptance, merging, and yielding. The

acceleration models for bus operators and other drivers might be assumed to be identical. Lane-

changing behavior, on the other hand, is fundamentally different between bus operators and other

drivers, and simulation models should reflect this difference.

Lane-changing theory assumes that each driver aims to minimize his or her travel time, and makes

discretionary lane changes based on the perceived utility of the alternative lanes, which is a function

of the relative speed of the vehicles in the target lane(s).

A bus operator might make discretionary lane changes between stops to increase travel speed

according to the same decision-making processes as other drivers, albeit with a preference toward the

lane with bus stops. However, mandatory lane-changing decisions, like changing into the extreme left

lane near the bus stops, will largely govern the bus operator lane-changing along a route. Thus the

location and spacing of stops along the route dictate to a great extent bus operator lane-changing.

Other factors affecting bus operator lane-changing that do not affect other drivers, such as the

presence of bus lanes and HOV lanes. Likewise, there are factors that affect other drivers but not the

bus operator. For instance, the private auto drivers traveling behind a bus in a lane that contains bus

stops will attempt to move out of the lane and overtake the bus in anticipation of the bus’ routine

stopping and starting at those stops.

Some simulation packages model the variation in familiarity with the network among the driving

population which governs various behaviors such as how far in advance of a turn or exit from the

current roadway a driver changes lane in order to make that turn or exit. A failure to capture bus

operator familiarity might cause a simulation model to overstate congestion when buses make late

lane change maneuvers.

Behavior at and near stops

Behavior at and near stops encompasses all behaviors in which a bus operator engages in order to pull

into a stop, serve passengers, and reenter the traffic stream.

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Dwell Time is the period of time during which a bus is stopped at a bus stop to serve passengers and

consists of dead time and service time. Dead time is the sum of time spent stopped with the doors

closed and the time spent to open and close the doors. The service time is the span of time during

which the doors are open for passengers to board and alight. Dwell time depends upon the weather,

bus stop design and passenger demand.

Vehicle movement near bus stops can also have a serious impact on the surrounding traffic stream and

on vehicle progression. This particularly includes pulling out of bus stops. Unrealistic, excessive

delays may arise if a simulation model does not reflect the way drivers in the adjacent traffic stream

yield to exiting buses, and thus may cause undue disruption of the bus’ progression. The yielding

behavior of other drivers, in turn, can have significant consequences with respect to congestion in the

general traffic stream.

TRANSIT DEMAND REPRESENTATION

Passenger demand is generally considered to be random. For instance, passenger demand can be

highly variable at the route level, the sub-route (or route segment) level and the bus stop level. The

geographic distribution of passenger demand is subject to the local land use patterns and the locations

of activity centers along a route. Passenger demand may have considerable temporal variability. For

example, passenger demand might vary by time of day (e.g. peak and off-peak) and day of the week

(e.g. weekday vs. weekend) and is subject to spiking due to special events (e.g. World Cup matches).

Large passenger demand (boarding and alighting passengers) at a bus stop and crowding on the bus

might cause delays at the stop, thus preventing the bus from departing on schedule. A lack of demand

at a bus stop, however, in the absence of dispatcher intervention or operating procedures that call for

holding, might cause the bus to depart early and therefore get ahead of its schedule.

The number of passengers boarding and alighting depends on passenger arrival patterns, which is

usually a function of the type of service. For example, it is generally assumed that transit passengers

tend to arrive more randomly as the service becomes more frequent and irregular. On the other hand,

as the service becomes more regular and infrequent, passengers tend to rely more heavily on the

schedule and thus time their arrivals at stops closer to the scheduled vehicle arrival time in order to

minimize waiting time.

Jolliffe and Hutchinson (1975) divided transit passengers into three categories:

The proportion q who arrive coincidentally with the bus and thus have no waiting time.

The proportion p who are familiar with the schedule and arrive close to the vehicle arrival

time and wait on average wmin.

The proportion (1-q)(1-p) who arrive randomly and wait on average wrand.

When passengers arrive randomly, wrand = µ(1+ µ2/σ

2)/2, where µ and σ are the mean and standard

deviation of the time headway between buses, respectively.

Based on measurements taken at bus stops in London, Joliffe and Hutchinson estimate p as a function

of the service characteristics:

Where g = wrand – wmin.

The value of g is the potential to reduce waiting time, and increases as the time headway between

buses increases. Therefore, p increases when bus services become more infrequent.

p = 1- exp (-λg)

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The value of λ was determined to be 0.131 and 0.015 for peak and off-peak conditions, respectively,

confirming a priori expectations that, during the peak, more passengers are familiar with the schedule

and arrive so as to minimize waiting time.

This dynamic interaction between the passenger and the service is the subject of a host of APTS

applications, including traveler information systems, and has significant operational implications with

respect to APTS that mean to monitor and control bus operations in real time.

APTS REPRESENTATION

Various APTS technologies, whether for collecting information, applying information (e.g. for real-

time control) or disseminating information, differ widely in their designs and their operations. Some

APTS are designed to function offline and are not directly involved with transit operations in real-

time. Among these offline technologies are Itinerary Planning Systems (fleet management, transit

operations software) and some automated service coordination applications. The outcomes of these

offline applications can be used as input to a simulation model.

The online APTS technologies that make up the bus surveillance system serve as the link between the

supply and demand components of the bus transit system. Surveillance includes the sensor

technologies, and their governing logic, used by transport service providers to monitor the

performance of the system. These sensor technologies might include installed roadside bus sensors or

automated vehicle location technologies (e.g. GPS) or communications technologies that allow the

bus to transmit information to the TMC.

Using the surveillance system, transport service providers can monitor bus progression and make

informed decisions regarding real-time control of each bus’ movement and behavior (e.g. dispatch or

hold at a bus stop). The surveillance system may also be used to generate real-time input to various

APTS control strategies, such as conditional bus signal priority, and various information systems,

such as in-terminal/wayside traveler information.

In order to simulate APTS at the operational level, a traffic model must be able to mimic the

functionality of the technologies (e.g. where information is generated and how it is shared) as they

operate in the real world rather than the technology’s own intrinsic capabilities.

A generic and flexible bus operations model should be able to replicate the types of information (e.g.

location, speed, load) that the technologies produce and mimic the mechanism for sharing that

information between the components of the bus system (e.g. TMC, control devices, vehicles).

MEASURES OF EFFECTIVENESS

When simulating APTS, it is important to consider the benefits and costs of implementing a particular

APTS application. This might involve cost-benefit analysis at various levels of the transport system

including:

System level

Route segment level

Bus stop level

Vehicle level

Passenger level

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The performance measures may be qualitative or quantitative. Qualitative factors include, for

example, passenger comfort, safety, and amenities at bus stops. Quantitative factors might include

monetary considerations, such as cost savings and revenue increases from increased ridership, or

service delivery measures, such as on-time performance and headway adherence.

The bulk of expected APTS benefits are quantitative gains that accrue either to the service provider

(e.g. cost savings, revenue increases) or to the passenger (e.g. reduced waiting and in-vehicle time).

APTS also produce benefits that occur in different parts of the network, such as at bus stops (e.g.

dwell time reduction), along a route segment (e.g. travel time, headway variability) and at the system

level (e.g. transit vs. auto travel times).

Therefore, performance measure output from traffic simulation should include data about the different

elements of the system in order to draw meaningful conclusions about the performance of APTS.

An example of measures of effectiveness for evaluating Traffic Signal Priority (Dale et. Al., 1999) is:

Measure of Effectiveness Description

Intersection Control Delay Total delay to all vehicles in queues at traffic

signals

Minor Movement Delay The delay at traffic signals to cross-street

movements and protected main-street left turns

Minor Movement Cycle Failures The event that vehicles performing minor

movements arrive during a red interval and are

unable to clear the intersection during the following green

Bus Travel Times The time it takes a bus to travel the length of a route or route segment

Bus Schedule Reliability The use of travel time variability (standard

deviation) as an indicator of reliability

Intersection Bus Delay Average delay to buses at an intersection

Average Person Delay Intersection control delay, intersection bus delay,

average automobile occupancies and bus loads to determine delay in seconds/person

Vehicle Emissions CO and NOx emissions on a segment basis

Accidents Transit vehicle accident frequency as a safety

measure

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CHAPTER 3: APTS IMPLEMENTATIONS

APTS have been and are being implemented in many developed/ developing countries in the world

viz. the US, Canada, Japan, Brazil, China etc. A FTA report Advanced Public Transportation System

Deployment in the United States- 1999, reveals that 212 transit agencies operate 361 service types

employing some form of advanced communications. Similar figures are available for other

technologies such as;

Automated transit information with 102 service types operated by 89 agencies

Paratransit computer assisted dispatching with 101 operational systems

Automatic vehicle location with79 service types operated by 61 agencies.

In India, a glowing example of the implementation of APTS is the BRT system in Indore city. The

following figure shows the technologies in vogue there.

APTS deployment in India is catching up because of BRTS coming up in cities like Pune, Ahmedabad

and Mysore and also because of the increased awareness about the benefits of such systems among

the Transportation agencies of other states and cities such as Hyderabad, Delhi, and Bangalore etc.

The following table shows the APTS services in public buses being used in some of the afore-

mentioned cities;

APTS Technology Implementing city

Traffic Signal Priority, Emergency Vehicle

Signal Preemption etc.

Mysore, Hyderabad

Automatic Fare Collection Mysore, Ahmedabad, Hyderabad

Public Information System-Plasma Screens,

Display boards at bus stops etc

Mysore, Hyderabad

Central Control Rooms Mysore, Ahmedabad

Page | 19

References

Daniel J. Morgan (2000). A Microscopic Simulation Laboratory for Advanced Public

Transportation System Evaluation. M.S. Thesis, Massachusetts Institute of Technology.

Federal Transit Administration. Advanced Public Transportation Systems: The State of the

Art Update 2000.

Robert F. Casey and John Collura (1994). Advanced Public Transportation Systems:

Evaluation Guidelines. Final Report, Office of Technical Assistance, Federal Transit

Administration.

Federal Transit Administration. Advanced Public Transportation Systems Deployment in the

United States Update, January 1999.

D.J. Dailey and M.P. Haselkorn (1994), Demonstration of an Advanced Public

Transportation System in the Context of an IVHS Regional Architecture. University of

Washington.

Dario Hidalgo and Aileen Carrigan (2010). Modernizing Public Transportation. EMBARQ,

the WRI Center for Sustainable Transport.

Detailed Project Report- ITS Solutions, Transit Signal Priority and Automated Fare

collection Systems, Indore BRTS.

Ministry of Urban Development, Govt. of India. Environment and Social Management

Framework. GEF/World Bank/UNDP-SUTP, India.