Traffic lights

The Icelandic Road and Coastal Administration and the six municipalities in the capital area share responsibility for traffic lights and traffic light control. The capital area is defined as one transportation zone. Control of traffic lights is a collaborative project among these entities. Traffic lights within each municipality's boundaries are owned by that municipality while traffic lights on main roads are owned by the Icelandic Road and Coastal Administration. A large portion of traffic lights are jointly owned by municipalities and the Icelandic Road and Coastal Administration. This occurs where main roads and municipal streets intersect.

The primary purpose of traffic lights is to ensure traffic flow at intersections where vehicles, pedestrians, and cyclists meet. Traffic lights control movement at intersections. They allow travelers from different directions to proceed safely and efficiently. The goals include:

• ensuring all travelers can proceed
• improving traffic flow to reduce congestion
• shortening travel times
• increasing traffic safety
• prioritizing emergency vehicles and public transportation on main routes

Over half of all traffic lights in the capital area are currently controlled through a central traffic light computer. The control computer receives real-time traffic information from each intersection. It adapts controls at each intersection based on current traffic volume. Plans call for connecting all traffic lights in the capital area to central control in coming years. Each traffic light also has a control box, which functions as a branch of the central computer. This box helps facilitate control and allows traffic light control to continue if connection to the central computer is lost.

The control box manages traffic lights and consists of several units. All light fixtures, button boxes, and sensors connect to the control box, and its safety system ensures proper traffic light function and correct response to disruptions.

Traffic lights are continually being renewed, with eight different types of control boxes in use, some over 30 years old. During renewal, connecting traffic lights to the CTCS is a priority to enable monitoring and quick response to malfunctions.

PDF

Most traffic lights are traffic-actuated and controlled by sensors. Some lights are pre-timed, with fixed green, yellow, and red light durations regardless of traffic volume. Traffic lights in main areas are coordinated with timing plans. These plans aim to minimize delays and ensure traffic safety. This doesn't mean drivers will hit green lights at every intersection. Controls are designed to reduce overall delays in the area.

Traffic-actuated lights use technology like sensors, software, communication networks, and artificial intelligence. This improves traffic light control at individual intersections or in specific areas. Sensors come in various forms, such as magnetic loops in the road, radar sensors, or cameras. Traffic light control in the capital area falls into three categories: pre-timed, semi-actuated, and fully-actuated.

• Pre-timed traffic lights, like those at Nóatún and Laugavegur intersection, have no sensors. Green light duration for different directions and pedestrian crossings is pre-defined. It doesn't change based on traffic volume. However, pre-timed settings account for varying traffic at different times of day. Meaning the control is not the same, for example, in the morning during heavy traffic and in the evening during lighter traffic.
• Semi-actuated intersections, like Bústaðavegur and Grensásvegur, use sensors. The main direction stays green until traffic is detected on side streets or a pedestrian button is pressed.

• At fully-actuated intersections, sensors send messages to a control box. It selects the best pre-designed timing based on traffic volume from different directions. New artificial intelligence technology allows for even better adaptation to current conditions. Equipment with this technology will be implemented in the capital area in coming months. Software on newer traffic lights can be updated to use this new technology.

  Map of traffic light types

Over half of all traffic lights are connected to the centralized traffic control system (CTCS), a Sitraffic Scala system. The goal is to connect all traffic lights to the CTCS.

One advantage of connecting traffic lights to the CTCS is immediate malfunction notifications, allowing for quick responses.

• Map of MSU connection

The current system runs on an automatic control called TASS (Traffic-Actuated Selection of Signal Programs). Its main benefit is selecting light settings based on current traffic volume for each TASS area.

The capital area is divided into five TASS areas:

1. Sæbraut
2. Miklabraut-Kringlumýrarbraut-Hringbraut-Suðurlandsbraut
3. Hafnarfjarðarvegur
4. Bústaðavegur
5. Breiðholtsbraut-Nýbýlavegur

Map of TASS area

Traffic lights on certain routes are synchronized to ensure optimal traffic flow. This allows drivers to maintain a steady speed without encountering red lights. This is commonly called the Green Wave. It works best when driving at or slightly below the speed limit. Several Green Waves are defined in the capital area, such as along Sæbraut, Bústaðavegur, and Hafnarfjarðarvegur.

Green Waves in both directions are rarely possible due to intersection layout and location. Lights are synchronized for the predominant traffic direction at any given time. Traffic lights on main roads are coordinated to facilitate traffic flow towards the city center and major employment areas in the mornings, and in the opposite direction in the afternoons and off-peak hours.

PDF - morning

PDF - afternoon

PDF - off-peak times

Reykjavík City regularly updates its traffic light systems.

Changes to a traffic light system are often based on recorded shifts in traffic patterns or volume at specific intersections.

These changes may include:

• Green lights are only given when needed
• Green light duration (time the traffic light shows green in one direction) is shortened if traffic is light
• Green light duration is extended in one direction if traffic is heavy

At many intersections, we detect traffic (including cyclists) approaching the intersection, so we only need to give a green light when someone needs it. Detection usually occurs in zones, with the last zone often located at the stop line. It's important to position yourself behind the stop line to be detected and ensure you get a green light.

If a sensor has malfunctioned or needs adjustment, it can affect system functionality, and you may have to wait longer at a red light than usual. This is often a problem for cyclists, as they are harder to detect. If a traffic light system suddenly behaves differently than usual, or you're concerned about a system malfunction, you can report various issues using the contact information at the top of the page.

Note: Green lights for cyclists are not given after cars have received a green light.

Sometimes, traffic lights may show red in all directions when no road users have been detected near the system. This situation is called "all red."

"All red" has a speed-limiting effect, as drivers who see a red light in the distance often slow down or stop. However, drivers who see a green light in the distance often speed up to cross the intersection. Drivers exceeding the speed limit on a road with "all red" lights may have to stop completely before the light turns green.

Drivers may also experience a green light in one direction even though no road users are visible in that direction. This may be because a cyclist or pedestrian was detected by the system but crossed before the lights changed to green. When the system detects traffic in one direction, there must always be a green period and a safety period, which may delay the green light in the opposite direction.

There can be various reasons why side streets always get a green light, even when there's no traffic. These reasons may include:

• High service level for pedestrians, ensuring they are always registered and given green lights.
• Desire for equal service levels for both driving directions at intersections.
• Malfunction in traffic detection from one direction. If there's equipment failure, traffic from this direction is registered in every cycle to ensure traffic flow.

There can be many reasons why you, as a driver, experience not getting a green wave on road sections where coordination actually exists. Reasons may include:

• The distance between traffic light systems doesn't always allow for optimal coordination in both directions. Some places prioritize green waves in one direction in the morning and the opposite direction in the afternoon.
• Your speed is much higher or lower than what was anticipated when timing the light changes.
• There's a big difference in the size of various traffic light systems on a coordinated road section. At intersections with smaller side streets, there can be a long green time, but at intersections with larger side streets, the green time is shorter.
• When we have coordination, there's a fixed green time in each traffic light system, which must occur at a certain time in each cycle. To increase service for road users, we detect traffic from side streets, and if it's quickly processed or non-existent, we can give green before reaching this "fixed" time. However, when we do this, we can't be sure that the next intersection will follow (e.g., if there's heavy side street traffic), and then we get extra stops.
• Sensor malfunctions can affect the traffic light system's engagement.

In a traffic-linked light system, we detect traffic and try to give green lights according to the traffic volume present at any given time.

Collecting traffic information is fundamental to centralized traffic control. Traffic sensors have been installed at several counting locations to detect and assess traffic volume. The sensors are connected to the CTCS, where information from sensors is used to select the most suitable light program at any given time.

PDF

Real-time information on the service level of the traffic flow

Real-time information about traffic volume and speed at selected locations

Reykjavík City usually installs traffic lights at major intersections where traffic volume and complexity require light control to ensure fast and safe traffic flow. This is done where general right-of-way rules no longer work efficiently.

In addition to efficient traffic control, traffic lights often provide a better sense of safety in traffic, as road users know they can cross intersections when the green light comes, and can trust that oncoming traffic will stop for them.

Installation of traffic light systems must be in consultation with the police in accordance with regulations on road markings.

The City consults with the Icelandic Association of the Blind to identify and prioritize which traffic light systems should get audio signals. Regular audio signals are usually active from 7am to 10pm to reduce noise pollution.

By nature, traffic lights are primarily there to ensure that everyone can get to their destination, regardless of the mode of transport used. This includes, for example, giving pedestrians the opportunity to safely cross a busy street and ensuring road users have enough time to cross.

In the policy document on traffic light control in the capital area, there will be an increased emphasis on designing traffic light controls that prioritize pedestrians and cyclists in the future, e.g., by minimizing waiting times for pedestrians and cyclists as much as possible and providing them with countdown information on lights, as is done on Lækjargata today. In addition, button boxes should be provided wherever pedestrians and cyclists travel so they can call for a green light.

Traffic light control is primarily to improve traffic safety and enable road users to travel in the safest way possible. Traffic light control alone will not solve all problems for the future, but other solutions such as efficient public transport, facilitating pedestrian and bicycle traffic, as well as the state and municipalities in the capital area working together to ensure efficient traffic on main roads, must also be considered.

Traffic lights vary by area and time as traffic volume is not always the same. The purpose of traffic light control is precisely to respond to this and minimize delays for all road users. Waiting time on side streets is usually longer than on main roads, as the latter usually get longer green times. The cycle length of traffic lights, where one cycle is the time that passes from when traffic lights turn red until they turn red again, is never longer than 90 seconds and shorter outside peak hours.

Ambulances and fire trucks get priority at traffic lights on certain routes. Equipment has been installed in the vehicles that automatically calls for priority at traffic lights when the vehicles drive with emergency lights on. The priority system aims to ensure increased safety in emergency driving, both for those in emergency vehicles and for general traffic affected by emergency driving.

Strætó Public Transport also has easier passage through intersections with this control, though it's not priority control like for the fire department. For Strætó, a device in the bus detects when it approaches an intersection and extends the green light duration in the bus's direction.

The priority system aims to ensure increased safety in emergency driving, both for those in emergency vehicles and for general traffic affected by emergency driving. It's also crucial to reduce response time when people are in life-threatening situations, especially during heavy traffic. The system has proven very effective.

PDF

Only LED lights are used when renewing traffic lights. In addition to being energy-efficient, LED lights are much more reliable and have a lower failure rate than traditional incandescent bulbs. More than half of traffic lights use LED lights.

PDF