User:Hoskir/Revision Request 4266

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copy all of 903.3.4

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903.3.4 Placement of Warning Signs (MUTCD Section 2C.04)

Support. Information on the placement of warning signs is contained in EPG 903.1.13 through 903.1.18.

The time needed for detection, recognition, decision, and reaction is called the Perception-Response Time (PRT). Table 903.3.4 is provided as an aid for determining warning sign location. The distances shown in Table 903.3.4 can be adjusted for roadway features, other signing, and to improve visibility.

Guidance. Warning signs should be placed so that they provide an adequate PRT. The distances contained in Table 903.3.4 should be applied with engineering judgment.

Minimum spacing between warning signs with different messages should be based on the estimated PRT for driver comprehension of and reaction to the second sign.

The effectiveness of the placement of warning signs should be periodically evaluated. This is typically accomplished during routine sign inspection cycles. EPG 903.1.19 contains information regarding MoDOT’s sign maintenance program.

Standard. When any part of a warning sign assembly (post, sign, plaque, etc.) is replaced, maintained or modified, the placement of the sign should be reviewed based on advance placement distances in Table 903.3.4. Additionally, mounting height should be reviewed for conformance with EPG 903.1.15.

Table 903.3.4 Guidelines for Advance Placement of Warning Signs

Posted or 85th-Percentile Speed	Advance Placement Distance1
	Condition A: Speed reduction and lane changing in heavy traffic2	Condition B: Deceleration to the listed advisory (mph) for the condition
		03	104	204	304	404	504	604	704
20 mph	225 ft	115 ft	N/A5	—	—	—	—	—	—
25 mph	325 ft	155 ft	N/A5	N/A5	—	—	—	—	—
30 mph	460 ft	200 ft	N/A5	N/A5	—	—	—	—	—
35 mph	565 ft	250 ft	N/A5	N/A5	N/A5	—	—	—	—
40 mph	670 ft	305 ft	100 ft6	100 ft6	N/A5	—	—	—	—
45 mph	775 ft	360 ft	125 ft	100 ft6	100 ft6	N/A5	—	—	—
50 mph	885 ft	425 ft	200 ft	175 ft	125 ft	100 ft6	—	—	—
55 mph	990 ft	495 ft	275 ft	225 ft	200 ft	125 ft	N/A5	—	—
60 mph	1100 ft	570 ft	350 ft	325 ft	275 ft	200 ft	100 ft6	—	—
65 mph	1200 ft	645 ft	450 ft	400 ft	350 ft	275 ft	200 ft	100 ft6	—
70 mph	1250 ft	730 ft	525 ft	500 ft	450 ft	375 ft	275 ft	150 ft	—
75 mph	1350 ft	820 ft	625 ft	600 ft	550 ft	475 ft	375 ft	250 ft	100 ft6
Note 1 — For Advanced Placement Distance — General The distances are adjusted for a sign legibility distance of 180 feet for Condition A. The distances for Condition B (with the exception of the potential stop condition) have been adjusted for a sign legibility distance of 250 feet, which is appropriate for an alignment warning symbol sign. For Conditions A and B, warning signs with less than 6-inch legend or more than four words, a minimum of 100 feet should be added to the advance placement distance to provide adequate legibility of the warning sign. Note 2 — For Condition A — Speed Reduction and Lane Change Conditions Typical conditions are locations where the road user must use extra time to adjust speed and change lanes in heavy traffic because of a complex driving situation or reduce to a new posted speed. Typical signs are Merge, Right Lane Ends, and Reduced Speed Ahead. The distances are determined by providing the driver a PRT of 14.0 to 14.5 seconds for vehicle maneuvers (2018 AASHTO Policy, Table 3-3, Decision Sight Distance, Avoidance Maneuver E) and adjusted for a legibility distance of 180 feet for the appropriate sign. Note 3 — For Condition B — Stop Condition Typical condition is the warning of a potential stop situation. Typical signs are Stop Ahead, Yield Ahead, Signal Ahead, and Intersection Warning signs. The distances are based on the 2018 AASHTO Policy, Table 3-1, Stopping Sight Distance, providing a PRT of 2.5 seconds, a deceleration rate of 11.2 feet/second2. Note 4 — For Condition B — Reduced Speed Conditions Typical conditions are locations where the road user must decrease speed to maneuver through the warned condition. Typical signs are Turn, Curve, Reverse Turn, Reverse Curve, or Reduced Speed Ahead. The distance is determined by providing a 2.5 second PRT, a vehicle deceleration rate of 10 feet/second2, and adjusted for a sign legibility distance of 250 feet. Note 5 — For Condition B — N/A Values No suggested distances are provided for these speeds, as the placement location is dependent on site conditions and other signing. An alignment warning sign may be placed anywhere from the point of curvature up to 100 feet in advance of the curve. However, the alignment warning sign should be installed in advance of the curve and at least 100 feet from any other signs. Note 6 — For Condition B — for shortest distance values per posted speed The minimum advance placement distance is listed as 100 feet to provide adequate spacing between signs. General Note: Warning signs that advise road users about conditions that are not related to a specific location can be installed in an appropriate location, based on engineering judgment.