User:Hoskir/Revision Request 4251
copy 903.3.29
903.3.29 Advance Traffic Control Signs (W3-1, W3-2, W3-3, and W3-4) (MUTCD Section 2C.35)
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Standard. The Stop Ahead (W3-1), Yield Ahead (W3-2), and Signal Ahead (W3-3) Advance Traffic Control signs shall be installed on an approach to a primary traffic control device that is not visible for a sufficient distance to permit the road user to respond to the device (see Table 903.3.4). The visibility criteria for a traffic control signal shall be based on having a continuous view of at least two signal faces for the distance specified in Table 902.4.6.
Guidance. Where intermittent obstructions occur, engineering judgment should determine the treatment to be implemented.
The minimum visibility distance of a signal for a facility with a speed limit above 60 mph should be determined by summing the stopping sight distance (see Table 903.3.1) and the assumed queue length. The assumed queue length should be determined by engineering judgment.
If an advance traffic control sign is warranted for an approach at an intersection of a MoDOT maintained road and non-MoDOT maintained road, the agency responsible for the maintenance of the non-MoDOT road should be notified of the condition.
Support. Permanent obstructions causing the limited visibility might include roadway alignment or structures. Intermittent obstructions might include foliage or parked vehicles.
Option. An Advance Traffic Control sign may be used for additional emphasis of the primary traffic control device, even when the visibility distance to the device is satisfactory.
Signal Ahead (W3-3) signs may be posted on the right- and left-hand sides of the road on a high speed divided approach.
Support. EPG 903.3.64 contains information about the use of an advance street name plaque to identify an intersecting road.
Option. A BE PREPARED TO STOP (W3-4) sign may be used to warn of stopped traffic caused by a traffic control signal in advance of a section of roadway that regularly experiences traffic congestion, history of crashes, or based on engineering judgement.
A Warning Beacon (see EPG 902.18.3) may be used with an Advance Traffic Control or BE PREPARED TO STOP (W3-4) sign. If a warning beacon is used, the beacon(s) may be activated before the start of the yellow change interval referred to as lead flash, which is the time before the onset of yellow at which the warning beacon(s) begin to flash. Recommended values for lead flash in accordance with the posted speed limit are specified in Table 903.3.29. If the traffic control signal goes to all-direction cabinet or programmed flash the warning beacon may also flash (see EPG 902.7 for additional information about flashing operation of traffic control signals).
| Posted Speed (mph) | Distance Between Warning Sign and Stop Line (ft) | Lead Flash, Advance Warning Before End of Green (sec) |
|---|---|---|
| 70 | 871 to 975 max** | 8 |
| 70 | 730 min* to 870 | 7 |
| 65 | 811 to 905 max** | 8 |
| 65 | 645 min* to 810 | 7 |
| 60 | 661 to 745 max** | 7 |
| 60 | 570 min* to 660 | 6 |
| 55 | 606 to 685 max** | 7 |
| 55 | 495 min* to 605 | 6 |
| 50 | 476 to 550 max** | 6 |
| 50 | 425 min* to 475 | 5 |
| 45 | 426 to 495 max** | 6 |
| 45 | 360 min* to 425 | 5 |
| *The advance traffic control sign shall not be installed less than this minimum distance. **The sign placement distance can exceed the "max" distance. The lead flash time should be determined by coordinating with the MoDOT Highway Safety and Traffic Division. | ||
Standard. When a BE PREPARED TO STOP (W3-4) sign is used in advance of a traffic control signal, it shall be used in addition to a Signal Ahead sign and shall be placed a minimum of 200 feet downstream from the Signal Ahead sign. The BE PREPARED TO STOP (W3-4) sign shall be installed as specified in Table 903.3.4 (See Figure 903.3.29.1).
A BE PREPARED TO STOP (W3-4) sign with a warning beacon shall not be considered for intersection approaches with a posted speed limit of 40 mph or less.
