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Full traffic signals are traditional green-amber-red displays for all directions of approaching traffic. Full signals are usually installed when intersections have delays and back-ups under two-way or all-way stops, often due to too much traffic.
Factors which reduce Traffic Flow
- Percentage of trucks in the traffic stream – they move slower and take longer thereby reducing capacity
- Transit Stops – buses stopping in a curb lane to pick up passengers can interrupt traffic flow
- Right turns – vehicles turning right can slow the flow of traffic in the curb lane especially if there are lots of pedestrians crossing
- Left turns – if there are no exclusive left turn lanes then a waiting left turn vehicle can severely delay traffic
- Grades – if the approach to an intersection is on an uphill grade then traffic will move slower
- Lane widths – drivers tend to drive slower when lane widths are narrow which impacts capacity
- Curb parking manoeuvres – vehicles backing into parking spaces can disrupt traffic flow
- Signal timing and phasing
Reasons for installing a full traffic signal control
The City‘s decision to install a full traffic signal control at an intersection is based on the current Ontario warrant outlined in Ontario Traffic Manual Book 12 (OTM Book 12) published by the Province of Ontario. Under this warrant, a traffic control signal would be technically supported if one of the following five following reasons is fulfilled:
- Minimum vehicle volumes – sets minimum volume criteria on all approaches and on side street approaches. There are separate volume criteria for restricted flow (urban) and free flow (rural) conditions.
- Delay to cross street – sets minimum volume criteria to reflect conditions where traffic volumes on the main road are so heavy those road users on the minor road suffer excessive delays. There are separate volume criteria for restricted flow (urban) and free flow (rural) conditions.
- Collision experience – sets a minimum number of collisions “preventable” by traffic signal control over a three year period. Five or more collisions in each of the three preceding 12 month periods are used as reason.
- Combination justification – makes provisions for conditions where two or more of reasons 1, 2 or 3 are met 80% of the time.
- Pedestrian volume – sets minimum pedestrian volumes and delays at a location for the installation of a traffic control device. This warrant is applicable to an intersection or mid-block location.
Traffic Signal Timing
Traffic signals operate in one of three modes- fixed time, semi-actuated, and fully actuated.
- Fixed Time - The traffic signal will continuously cycle for each roadway. A pre-set amount of time is allocated to each direction.
- Semi-Actuated - The major roadway receives green unless vehicles are on the minor roadway or if a pedestrian pushes the pushbutton to cross the major roadway is detected. In ground or overhead detection in the approach lanes of the minor street are used. This type of control is used where the major street has more traffic than the minor street.
- Fully-Actuated - There are vehicle detectors located in all of the approach lanes to the traffic signal. The amount of green time for each traffic movement will vary according to the number of vehicles detected.
- Coordination - Traffic signals along minor roadways throughout the city are ‘synchronized’ to enhance the operation of one or more directional movements that are programmed to a specific time of day along the corridor. Traffic signal timing plans are calculated using the posted speed limit.
Advance Left-Turn Phasing
- Staff regularly access the need for left-turn phasing at traffic signals based on the following criteria:
- The presence of an exclusive left-turn lane
- Delay to through traffic in combination left and through lanes
- Delay and queuing based on the following:
- Volume of left-turning traffic
- Volume of opposing traffic
- Availability of gaps based on pedestrian crossing volumes
- Emergency detour routes and mountain access points
- Left-turn collision statistics
- Site distance measurements
- Transit operations and schedule adherence
- Approved development applications that generate increased traffic
- We also access undesirable side effects that left-turn phasing can cause such as:
- Neighbourhood traffic infiltration;
- Increased delay and queuing for other directions of travel
- Delays to pedestrians
- Cost of additional equipment, wiring and vehicle detection equipment
- Overall effect on the entire traffic network by increasing cycle lengths
- Progression and coordination of adjacent traffic signals
Traffic Signal Vehicle Detection
Detection used throughout the City of Hamilton
- In ground inductive loops are used, these loops are able to detect when a vehicle is present which notifies the traffic signal controller. The vehicle must be positioned behind the while stop bar in order to be properly detected.
- The City uses video detection which monitors and sends live traffic feeds to the Traffic Management Centre, and also detects vehicles using a processor notifying the traffic controller when a vehicle is present.
What is the difference between a Red Light and a Vehible Detection Camera?
- A Red Light Camera is a type of traffic enforcement camera that an image of a vehicle which has entered an intersection during the all red phase.
- Detection Cameras are solely used to detect the presence of vehicles, and modify signal timings accordingly using a processor. The City of Hamilton does not record video or license plates.
Centralized Traffic Control System
Currently the City of Hamilton has over 100 signalized intersections under computer control at our Traffic Management Centre, located at 1375 Upper Ottawa Street.
The Traffic Signal System
- Adjust Signal Timings to accommodate traffic conditions from the Traffic Management Centre.
- Records functionality for legal purposes
- Maintains time clocks within our traffic controllers, in order to retain synchronization along various corridors throughout the City.
- Monitors operation of traffic signals and improves response time to damaged vehicle/pedestrian detection equipment, current traffic conditions and reporting.
- Implements Signal Timing Plans used for emergency and construction detour routes.
Traffic Control System Communication
The Traffic Management Centre communicates to our traffic signals using 5.8 GHz radio technology installed at the intersections which use point-to-multipoint communication.. The radio technology utilizes standard TCP/IP Ethernet protocols. Not only do we communicate to our traffic signals using this medium, we also receive live video feed from our peripheral devices. The City of Hamilton will also be installing fibre during major road construction.
Traffic signal issues & requests
For issues relating to traffic signal operation, contact Traffic Operations & Engineering Services by:
- Phone: 905-546-4376
- Email: [email protected]
Traffic signal operation requests could include:
- New traffic signals
- Advance left turns
- Pedestrian signals
- Pedestrian walk times
- Red light cameras
Traffic Operations and Engineering
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