Slide 1

Office of Traffic, Safety, and Operations 1 Signing by Type of Interchange Figures 2E-25 through 2E-30 show applications of guide signs for common types of interchanges. The figures will be looked at in detail in following sections. The interchange layouts shown in most of the figures illustrate only the major guide signs for one direction of traffic on the through road and on the crossroad. 2E. 40 Slide 2 Office of Traffic, Safety, and Operations 2 Signing by Type of Interchange The signing layout for all interchanges having only one exit ramp in the direction of travel should be similar, regardless of the interchange type. For the sake of uniform application, the significant features of the signing plan for each of the more frequent kinds of interchanges (illustrated in Figures 2E-27 through 2E-38) should be followed as closely as possible. Even when unusual geometric features exist, variations in signing layout should be held to a minimum. 2E. 40 Slide 3 Office of Traffic, Safety, and Operations 3 Freeway-to-Freeway Interchange Freeway-to-Freeway interchanges are major decision points where the effect of taking a wrong ramp cannot be easily corrected. Reversing direction on the connecting freeway or re-entering to continue on the intended course is usually not possible.2E.41 Slide 4 Office of Traffic, Safety, and Operations 4 Freeway-to-Freeway Interchange Sign messages should contain only the route marker, cardinal direction, and the name of the next control city on the route. At splits where the off-route movement is to the left or where there is an optional lane split, diagrammatic signs should be used at the Advance Guide Sign location.2E.41 Slide 5 Office of Traffic, Safety, and Operations 5 Freeway-to-Freeway Interchange Overhead signs shall be used at a distance of 1 mile and at the theoretical gore of each connecting ramp. Overhead signs may also be used at the mile and 2 mile points. The arrow and/or control city may be omitted on signs that indicate the straight- ahead continuation of a route.2E.41 Slide 6 Office of Traffic, Safety, and Operations 6 Freeway-to-Freeway Interchange Figure 2E-272E.41 Slide 7 Office of Traffic, Safety, and Operations 7 Cloverleaf Interchange A cloverleaf interchange has two exits for each direction of travel The exits are closely spaced and have common Advance Guide Signs2E.42 Slide 8 Office of Traffic, Safety, and Operations 8 Cloverleaf Interchange The AG signs should include two place names, one corresponding to each ramp, with the name of the place served by the first exit on the upper line2E.42 Slide 9 Office of Traffic, Safety, and Operations 9 Cloverleaf Interchange Overhead signs shall be placed at the theoretical gore point of the first exit ramp, with an upward slanting arrow on the Exit Direction sign and the message XX MILE on the AG sign for the second exit.2E.42 Slide 10 Office of Traffic, Safety, and Operations 10 Cloverleaf Interchange The second exit shall be indicated by an OH Exit Direction sign over the auxiliary lane. An Exit sign shall also be used at each gore. Diagrammatic signs shall NOT be used.2E.42 Slide 11 Office of Traffic, Safety, and Operations 11 Cloverleaf Interchange Figure 2E-28 The Exit Direction sign for the second exit should be mounted on the structure if the mainline passes under the crossroad2E.42 Slide 12 Office of Traffic, Safety, and Operations 12 Cloverleaf Interchange with C-D Roadways 2E.43 Signing on the collector-distributor roadways should be the same as the signing on the mainline of a cloverleaf interchange. Guide signs at exits from the collector- distributor roadways shall be overhead and located at the theoretical gore of the collector-distributor roadway and the exit ramp. Slide 13 Office of Traffic, Safety, and Operations 13 Cloverleaf Interchange with C-D Roadways 2E.43 Figure 2E-29 Slide 14 Office of Traffic, Safety, and Operations 14 Auxiliary Lane Signing This section outlines uniform signing standards for auxiliary lanes on freeways, with and without escape lanes. The following layouts should be used in the appropriate situation. 1.Auxiliary lane less than 1/2 mile in length, without escape lane (See Figure 6.29A). 2.Auxiliary lane less than 1/2 mile in length, with escape lane (See Figure 6.29B). 3.Auxiliary lane 1/2 mile in length or greater, without escape lane (See Figure 6.29C). 4.Auxiliary lane 1/2 mile in length or greater, with escape lane (See Figure 6.29D).6-7.02.03 Slide 15 Office of Traffic, Safety, and Operations 15 Auxiliary Lane Signing Figure 6.30A (< mi w/o escape)6-7.02.03 Slide 16 Office of Traffic, Safety, and Operations 16 Auxiliary Lane Signing Figure 6.30B (< mi with escape)6-7.02.03 Slide 17 Office of Traffic, Safety, and Operations 17 Auxiliary Lane Signing Figure 6.30C (> mi w/o escape)6-7.02.03 Slide 18 Office of Traffic, Safety, and Operations 18 Auxiliary Lane Signing Figure 6.30D (> mi with escape)6-7.02.03 Slide 19 Office of Traffic, Safety, and Operations 19 Partial Cloverleaf Interchange Typical application of guide signs for partial cloverleaf interchanges is shown in Figure 2E-30.2E.44 Slide 20 Office of Traffic, Safety, and Operations 20 Partial Cloverleaf Interchange As shown in Figure 2E-30, the overhead Exit Direction sign should be placed on the structure if the mainline passes under the crossroad and the exit roadway is located beyond the structure.2E.44 Slide 21 Office of Traffic, Safety, and Operations 21 Diamond Interchange The typical diamond interchange ramp departs from the mainline roadway such that a speed reduction generally is not necessary in order for a driver to safely negotiate an exit maneuver from the mainline onto the ramp roadway. When a speed reduction is not necessary, an exit speed sign should not be used.2E.45 Slide 22 Office of Traffic, Safety, and Operations 22 Diamond Interchange The Exit Speed sign should be located along the deceleration lane or along the ramp such that it is visible to the driver far enough in advance so that a safe slowing and exiting maneuver can be made.2E.45 Slide 23 Office of Traffic, Safety, and Operations 23 Diamond Interchange A Stop Ahead or Signal Ahead warning sign may be placed, where engineering judgment indicates a need, along the ramp in advance of the cross street, to give notice to the driver (see Section 2C.26). When used on two-lane ramps, Stop Ahead or Signal Ahead signs should be used in pairs with one sign on each side of the ramp.2E.45 Slide 24 Office of Traffic, Safety, and Operations 24 Diamond Interchange Figure 2E-312E.45 Slide 25 Office of Traffic, Safety, and Operations 25 Diamond Interchange in an Urban Area A typical application of guide signs for diamond interchanges in an urban area is shown in Figure 2E-32. This example includes the use of the Community Interchanges Identification sign (see Section 2E.38) which might be useful if two or more interchanges serve the same community. In urban areas, street names are often shown as the principal message in destination signs.2E.46 Slide 26 Office of Traffic, Safety, and Operations 26 Diamond Interchange in an Urban Area Figure 2E-322E.46 Slide 27 Office of Traffic, Safety, and Operations 27 Diamond Interchange in an Urban Area If interchanges are too closely spaced to properly locate the Advance Guide signs, they may be placed closer to the exit, and the distance figures adjusted accordingly.2E.46 Slide 28 Office of Traffic, Safety, and Operations 28 Closely-Spaced Interchanges When a series of interchanges is closely spaced, the advance guide sign for the next interchange may be mounted on an overhead structure located downstream from the gore of the preceding interchange. Interchange Sequence signs should be used at closely spaced interchanges. When used, they should identify and show street names and distances for the next two or three exits as shown in Figure 2E-23.2E.47 Slide 29 Office of Traffic, Safety, and Operations 29 Closely-Spaced Interchanges 2E.47 Slide 30 Office of Traffic, Safety, and Operations 30 Closely-Spaced Interchanges Advance Guide signs for closely spaced interchanges shall show information for only one interchange.2E.47 Slide 31 Office of Traffic, Safety, and Operations 31 Minor Interchange At least one Advance Guide sign and an Exit Gore sign shall be placed at a minor interchange. An Exit Direction sign should also be used.2E.48 Slide 32 Office of Traffic, Safety, and Operations 32 Minor Interchange Figure 2E-332E.48 Slide 33 Office of Traffic, Safety, and Operations 33 Signing of Approaches and Connecting Roadways The freeway or expressway signing standards should be extended to the approach roadways because conventional guide signing on the approach roads, as described in Chapter 2D, might in some cases be ineffective for some of the more important interchanges. Guide signing for frontage roads should be consistent with the requirements for freeways and expressways.2E.49 Slide 34 Office of Traffic, Safety, and Operations 34 Signing of Approaches and Connecting Roadways Consistently applied signing for conventional road approaches to freeway or expressway interchanges is highly desirable.2E.49 Slide 35 Office of Traffic, Safety, and Operations 35 Signing of Approaches and Connecting Roadways The signing of conventional roads with one lane of traffic approaching an interchange should consist of a sequence containing the following signs: Junction Assembly Destination Sign Directional Assembly or Entrance Direction Sign for the first ramp Advance Route Turn Assembly or Advance Entrance Direction Sign with an advance arrow turn Directional Assembly or Entrance Direction Sign for the second ramp2E.49 Slide 36 Office of Traffic, Safety, and Operations 36 Signing of Approaches and Connecting Roadways Figure 2E-342E.49 Slide 37 Office of Traffic, Safety, and Operations 37 Signing of Approaches and Connecting Roadways Figure 6.26 unsignalized2E.49 Slide 38 Office of Traffic, Safety, and Operations 38 Signing of Approaches and Connecting Roadways Figure 6.27 signalized2E.49 Slide 39 Office of Traffic, Safety, and Operations 39 Signing of Approaches and Connecting Roadways At minor interchanges, the following sequence of signs may be used: Junction Assembly Directional Assembly for the first ramp Directional Assembly for the second ramp2E.49 Slide 40 Office of Traffic, Safety, and Operations 40 Signing of Approaches and Connecting Roadways Figure 2E-352E.49 Slide 41 Office of Traffic, Safety, and Operations 41 Signing of Approaches and Connecting Roadways On multi-lane conventional roads approaching an interchange, the sign sequence should contain the following signs: Junction Assembly Advance Entrance Direction Sign(s) for both directions (if applicable) of travel on the freeway or expressway Entrance Direction Sign for first ramp Advance Route Turn Assembly Entrance Direction Sign for the second ramp2E.49 Slide 42 Office of Traffic, Safety, and Operations 42 Signing of Approaches and Connecting Roadways Figure 2E-362E.49 Slide 43 Office of Traffic, Safety, and Operations 43 Signing of Approaches and Connecting Roadways Figure 2E-372E.49 Slide 44 Office of Traffic, Safety, and Operations 44 Signing of Approaches and Connecting Roadways Figure 2E-382E.49 Slide 45 Office of Traffic, Safety, and Operations 45 Wrong-Way Traffic Control at Interchange Ramps At interchange exit ramp terminals where the ramp intersects a crossroad in such a manner that wrong-way entry could inadvertently be made, the following signs shall be used: At least one ONE WAY sign for each direction of travel on the crossroad shall be placed where the exit ramp intersects the crossroad. At least one DO NOT ENTER sign shall be conspicuously placed near the end of the exit ramp in positions appropriate for full view of a road user starting to enter wrongly.2E.50 Slide 46 Office of Traffic, Safety, and Operations 46 Wrong-Way Traffic Control at Interchange Ramps At least one WRONG WAY sign shall be placed on the exit ramp facing a road user traveling in the wrong direction.2E.50 Slide 47 Office of Traffic, Safety, and Operations 47 Wrong-Way Traffic Control at Interchange Ramps Figure 2E-392E.50 Slide 48 Office of Traffic, Safety, and Operations 48 Wrong-Way Traffic Control at Interchange Ramps In addition, the following pavement markings should be used: On two-lane paved crossroads at interchanges, double solid yellow lines should be used as a centerline for an adequate distance on both sides approaching the ramp intersections. Where crossroad channelization or ramp geometrics do not make wrong-way movements difficult, a lane use arrow should be placed in each lane of an exit ramp near the crossroad terminal where it will be clearly visible to a potential wrong-way road user.2E.50 Slide 49 Office of Traffic, Safety, and Operations 49 Wrong-Way Traffic Control at Interchange Ramps 2E.50 Slide 50 Office of Traffic, Safety, and Operations 50 Wrong-Way Traffic Control at Interchange Ramps The following traffic control devices may be used to supplement the above signs and pavement markings: Additional ONE WAY signs may be placed, especially on two-lane rural crossroads, appropriately in advance of the ramp intersection to supplement the existing ONE WAY sign(s). Additional WRONG WAY signs may be used.2E.50 Slide 51 Office of Traffic, Safety, and Operations 51 Wrong-Way Traffic Control at Interchange Ramps Slender, elongated wrong-way arrow pavement markings intended primarily to warn wrong-way road users that they are going in the wrong direction may be placed upstream from the ramp terminus, as shown in Figure 2E-39, to indicate the correct direction of traffic flow. The markings may consist of pavement markings or bidirectional red-and- white raised pavement markers or other units that show red to wrong- way road users and white to other road users.2E.50 Slide 52 Office of Traffic, Safety, and Operations 52 General Service Signs Approved symbols shall be permitted as alternatives to word messages, but shall not be mixed2E.51 Slide 53 Office of Traffic, Safety, and Operations 53 General Service Signs If the services are not visible from the ramp of a single-exit interchange, the sign shall be repeated at the ramp terminal with arrows These signs are generally not appropriate at major interchanges and in urban areas Distance to services should be shown where distance are greater than 1 mi.2E.51 Slide 54 Office of Traffic, Safety, and Operations 54 General Service Signs Signing should only be provided at locations where the road user can return to the freeway and continue in the same direction of travel2E.51 Slide 55 Office of Traffic, Safety, and Operations 55 LOGO Signing Program Logo Signs are permitted on interstates and urban controlled-access highways as specified in the Logo Sign Franchise Program Agreement 90212-P.6-7.09.09 Slide 56 Office of Traffic, Safety, and Operations 56 LOGO Signing Program Existing Mn/DOT-installed General Service Signs should remain in place at each interchange if all businesses are not accommodated in the Logo Sign Franchise Program. The State Signing Engineer, OTSO, in conj. with district offices shall review and approve all proposed logo installation locations to verify the signs will not have a negative impact on other required signing and that spacing is maintained.6-7.09.09