2015 Traffic Signals 101

Topic 1Why?

2

Office

of T

raffi

c, S

afet

y, a

nd

Tech

nolo

gyWhy?

• Who initiates a signal?• Developer• City/County• Politician• Public• State

3

Office

of T

raffi

c, S

afet

y, a

nd

Tech

nolo

gyWhy?

• Signal Warrants• Traffic control signals should not be installed

unless one or more of the signal warrants in the MN MUTCD are met

• The satisfaction of a warrant or warrants is not in itself justification for a signal

• Information should be obtained by means of engineering studies and compared with the requirements set forth in the warrants

• An Intersection Control Evaluation report needs to be prepared (see slide 8)

4

Office

of T

raffi

c, S

afet

y, a

nd

Tech

nolo

gyWhy?

• Warrant 1 - Eight-Hour Vehicular Volume• Warrant 2 - Four-Hour Vehicular Volume• Warrant 3 - Peak Hour• Warrant 4 - Pedestrian Volume

Signal Warrants

5

Office

of T

raffi

c, S

afet

y, a

nd

Tech

nolo

gyWhy?

• Warrant 5 - School Crossing • Warrant 6 - Coordinated Signal System• Warrant 7 - Crash Experience• Warrant 8 - Roadway Network• Warrant 9 - Intersection Near a Grade

Crossing

Signal Warrants

6

Office

of T

raffi

c, S

afet

y, a

nd

Tech

nolo

gyWhy?

• Warrant 1 Example• The Minimum Vehicular Volume, Condition A, is

intended for application at locations where a large volume of intersecting traffic is the principal reason to consider installing a traffic control signal

• The Interruption of Continuous Traffic, Condition B, is intended for application at locations where condition A is not satisfied and where the traffic volume on a major street is so heavy that traffic on a minor intersecting street suffers excessive delay or conflict in entering or crossing the major street

Warrant 1 tables

7

Office

of T

raffi

c, S

afet

y, a

nd

Tech

nolo

gyWhy?

TimeTotal of Both Major Street. Approaches

Higher Minor Street Approach

Total of Both Major Street. Approaches

Higher Minor Street Approach

Hour Satisfied?

6:00 to 7:00 650 205 600 200 Yes7:00 to 8:00 690 250 600 200 Yes8:00 to 9:00 640 201 600 200 Yes9:00 to 10:00 600 190 600 200 No10:00 to 11:00 550 100 600 200 No11:00 to 12:00 560 120 600 200 No12:00 to 1:00 600 160 600 200 No1:00 to 2:00 590 130 600 200 No2:00 to 3:00 580 180 600 200 No3:00 to 4:00 600 190 600 200 No4:00 to 5:00 630 220 600 200 Yes5:00 to 6:00 700 250 600 200 Yes6:00 to 7:00 680 230 600 200 Yes7:00 to 8:00 550 200 600 200 No8:00 to 9:00 450 190 600 200 No9:00 to 10:00 400 100 600 200 No

Warrant not met for Condition A (6 of 8 hours met)

Vehicles Per Hour Minimum Required

600 200

8

Office

of T

raffi

c, S

afet

y, a

nd

Tech

nolo

gyWhy?

• Intersection Control Evaluation (ICE)• In the past, the only perceived solution to

traffic delay and safety problems for at-grade intersections was the installation of a traffic signal

• Based on Signal Justification Reports (SJR)• Other options including stop control,

roundabouts, and unconventional reduced-access intersections, may be acceptable alternatives

ICE Book

9

Office

of T

raffi

c, S

afet

y, a

nd

Tech

nolo

gyWhy?

• ICE Definition• Intersection Control Evaluation, or ICE, is

a process that identifies the best intersection control through a comprehensive analysis and documentation of the technical (safety and operational), economic, and political issues of viable alternatives

10

Office

of T

raffi

c, S

afet

y, a

nd

Tech

nolo

gyWhy?

• Purpose of ICE• Evaluate various intersection designs• Select the optimal control for an

intersection based on an objective analysis for the existing conditions and future needs

• Document all technical, financial, and political issues in the ICE Report

• Replaces the SJR

11

Office

of T

raffi

c, S

afet

y, a

nd

Tech

nolo

gyWhy?

12

Office

of T

raffi

c, S

afet

y, a

nd

Tech

nolo

gyWhy?

• Cover ManualsSignal & Lighting

Certification

Roadway LightingDesign Manual

Minnesota Manualon Uniform Traffic

Control Devices(MN MUTCD)

Signal Design Manual(Update in 2014)

Office

of T

raffi

c, S

afet

y, a

nd

Tech

nolo

gyWhy?

• Cover Manuals

StandardSpecifications

Traffic EngineeringManual (TEM)

Signal Optimizationand Timing Manual

14

Office

of T

raffi

c, S

afet

y, a

nd

Tech

nolo

gyWhy?

• For up-to-date information, visit:• http://www.dot.state.mn.us/trafficeng/