Minimizing the impact of

latest MUTCD on

traffic signal operation

Presented by

Jose Guedes, T.E.

ITE 2015 Western District Annual Meeting

July 19-22, 2015

Las Vegas, Nevada

2014 California MUTCD

• Source: 2009 FHWA MUTCD

• Revised and approved by Caltrans in 2012

• Updated in November 2014

2014 California MUTCD

• Pedestrian Clearance interval

• Bicycle Minimum Green Time

• Minimum Yellow Change Interval

Pedestrian Clearance Interval

• WALK time (7 sec.)

• Pedestrian Clearance Time (3.5 ft/sec)

� Flashing DON’T WALK time

� Buffer time (3 seconds)

Pedestrian Clearance Time

• Ramp to Ramp (longest)

• Curb to Curb (shortest)

• Ramp to Curb extension (average)

Crossing distance

Crossing distances options

120 ft140 ft

ramp

curb

curb

ramp

120 ft108 ft

110 ft

116 ft

Curb to Curb

Pedestrian Crossing Distance

Ramp to ramp

140 ft123 ft

127 ft

127 ft

35 sec31 sec

32 sec

33 sec

Pedestrian Clearance Time

40 sec36 sec

37 sec

37 sec

Curb to Curb Ramp to ramp

Crossing speed = 3.5 ft/sec

Buffer Interval

28 sec24 sec

25 sec

26 sec

Flashing DON’T WALK

29 sec

30 sec

30 sec

Curb to Curb Ramp to ramp

5 sec 2 sec

33 sec

28 sec24 sec

25 sec

26 sec

Flashing DON’T WALK

Curb to Curb

5 sec 2 sec

40 sec36 sec

37 sec

37 sec

Ramp to ramp

Best case Worst case

Bicycle Minimum Green Time

140 ft

152 ft

155 ft

145 ft 140 ft

Bicycle Crossing distances

130 ft

127 ft

137 ft

Bicycle Minimum Green Time

10 sec

11 sec

11 sec

10 sec 9 sec

8 sec

8 sec

9 sec

Bicycle Minimum Green Time

• Video detection and /or bicycle loops

� Detects cars and bicycles

� Provide separate inputs into controller

• Radar detection

� Detects cars or bikes in the intersection

� Holds call until vehicle path is clear

Hardware solutions

Yellow Clearance

• The minimum yellow change interval for through traffic

movement shall be determined by using the 85th percentile

speed of free-flow traffic rounded up to the next 5 mph

increment.

• Where the posted or prima facie speed limit is higher than the

rounded value, use the posted or prima facie speed limit for

determination of the minimum yellow change interval for the

through traffic movement.

• See Table 4D-102(CA) sub-heading “a”.

2014 CA MUTCD

Yellow Clearance

• If the 85th percentile speed data is not available, the minimum

yellow change interval for through traffic movements shall be

determined by:

� adding 7 miles per hour to the posted or prima facie speed

limits of 30 mph or higher, and

� by adding 10 miles per hour to the posted or prima facie

speed limits of 25 mph or less.

• See Table 4D- 102(CA) sub-heading “b”.

2014 CA MUTCD

Minimum Yellow

2014 CA MUTCD

Speed85th Percentile is

available

Based on Posted

Speed (no 85th)

15 3.0 3.0

20 3.0 3.2

25 3.0 3.6

30 3.2 3.7

35 3.6 4.1

40 3.9 4.4

45 4.3 4.8

50 4.7 5.2

55 5.0 5.5

60 5.4 5.9

65 5.8 5.9

Other parameters that affect traffic

operations

• Vehicle extension

� extend green time

• Detector Lock

� Locks a call during yellow or red

� Detector call is released next green

Vehicle Extension

• Extension, Passage time = 5 sec

• 50 mph, Advance detector at 345 ft.

5 sec

4321043210 55

Vehicle Extension

• Extension = 2 sec

• Advance Loop extension = 3 sec

5 sec

2121010 32

Detector Lock

• Exploit some of MUTCD’s not clearly defined concepts,

such as the method to measure pedestrian crossing

distances – use the shortest distance;

• Understand MUTCD’s formulas and options, and always

reduce the timing parameters by using all available

options, such as reducing the Bicycle minimum green and

the Pedestrian Clearance, by subtracting both Yellow and

All-red intervals.

How to minimize MUTCD impact on

traffic signal operation?

• Use hardware solutions, such as video detection and radar-

based detection , to reduce minimum greens

• Fine-tune other timing parameters, such as Vehicle

Extension and Detector Lock, to further limit the amount of

wasted time during signal operation

How to minimize MUTCD impact on

traffic signal operation?

QUESTIONS