Emergency vehicles travel times have reduced since the priority system was introduced (Pic: Aaron Coghill)
Existing equipment used in Australian emergency vehicle ‘green wave’ trial.
Despite the lights and sirens, accidents between the motoring public and emergency vehicles on their way to/from the scene of an incident are relatively frequent. Figures from various sources indicate that road accidents are the second most frequent cause of death for on-duty fire fighter fatalities and that more than 90% of ambulance and fire engine accidents occur when the lights are on and the sirens wailing. Other studies indicate that the majority of ambulance accidents occurs when making turns or when broadsided at an intersection.
In an emergency situation such an accident has the potential to be a double tragedy with loss of life at the accident and the delay in getting to the original incident can be fatal for the victim or victims. After the accident the emergency fleet is one vehicle down which can have serious consequences and there are significant repair or replacement costs. With the imposition of emergency travel times adding further urgency to the need to attend a fire, accident or stricken individual and the traffic in many cities getting heaver, all the ingredients are in place for this trend to continue.
While, for obvious reasons, few would want to see emergency vehicles prevented from passing traffic lights during the stop phase, all would welcome moves to reduce the frequency of accidents that occur when they do. So in an effort to both minimise travel times and the potential for emergency vehicle accidents, the government of Queensland, Australia, is working with local ITS specialist supplier796 Transmax to develop an Emergency Vehicle Pre-emption (EVP) system.
The system automatically manages traffic signals before and after an emergency response vehicle passes the intersection. Essentially, the system interrupts the normal traffic light sequencing to turn the lights to green ahead of emergency vehicles and, more importantly, set the signals for the crossing traffic to stop. The resulting ‘green wave’ reduces both the emergency vehicle’s journey time and the potential for it to be involved in accidents at signal-controlled intersections.
Transmax says that while other systems can provide similar green wave functionality they typically require additional hardware either in the vehicles or at the signals. The aim of the Queensland project was to provide an intelligent EVP solution without the need for additional hardware in the vehicles or signals and without increasing the work load complexity for front-line officers. The subsequent EVP system being trialled in Queensland works without any specialist hardware in the vehicles or at the traffic signals and without any modifications to front-line officer operating procedures.
“Utilising the existing systems avoids the additional cost and complexity of installing additional equipment in the emergency vehicles,” Jason Wagstaff, chief operating officer with Transmax, told1846 ITS International.
The EVP system was delivered through a partnership between the7026 Department of Transport and Main Roads Queensland, Department of Community Safety Queensland and Transmax.
The Department of Community Safety developed the part of the system used to track the location of ambulances and fire emergency vehicles. This automatically starts working once the crew responding to an emergency call activated the warning lights (it is not necessary to use the sirens to trigger EVP). All tracking information is obtained from the mobile data terminals already installed in emergency vehicles.
Using computer-aided dispatch, GPS and traffic management technology, the EVP system not only determines the position of the vehicle but its trajectory and speed to calculate how long it will take to arrive at the next set of traffic lights. It then sends a message to the traffic control system to provide a green traffic signal in advance of the emergency vehicle’s arrival. Depending on when in the cycle the vehicle is expected to arrive at the intersection, the system either changes the sequence or extend/shorten the phases to ensure the emergency vehicle encounters a green light.
To handle the on-demand change required by the EVP system, Transmax developed a version of its Streams traffic light control software that accepts dynamic interventions while minimising the impact on other traffic. The revised system maintains pedestrian clearance protection, live monitoring at traffic management centres and user-configurable recovery algorithms.
The system operates fully automatically, although it also provides monitoring information to allow human intervention if an operator needs to override the system if for example an unintended queue builds up at the intersection. Wagstaff says this is ‘only expected to be used in very rare cases, and has not been experienced to date.’
A pilot deployment of the system was implemented in November 2012 in the city of Southport (population around 30,000), on the Gold Coast of Queensland. In total 20 emergency vehicles (10 ambulances and 10 fire engines) are participating in the ongoing trial encompassing 50 of Southport’s main intersections.
Preliminary results to date shows the EVP system is successfully detecting and providing a green wave for approaching emergency vehicles with their warning lights and sirens activated. Once the emergency vehicle has passed the system reverts to its normal sequencing and timing.
The emergency services in Southport respond to more than 100 incidents per week and preliminary results show the EVP-enabled vehicles benefit from more than 600 green traffic lights every week. Initial analysis indicates that travel times along major routes have been reduced by between 10% and 18% resulting in improved response times.
“While emergency vehicles can legally cross red lights normal motorists cannot so some of the improvement is due to it being easier for other drivers ahead of the emergency vehicle to get out of the way,” says Wagstaff. “Because the lights are green when the emergency vehicle approaches, it also reduces the number of unpredictable reactions by drivers in traffic queues at red traffic lights attempting to move out of the way.”
In reducing the number of times an emergency response vehicle needs to cross intersections against a red traffic light during the trial, the Department of Community Safety says “emergency responders using the system indicated a significant improvement in perceived safety.” It adds that as it does not have enough data to reasonably quantify the improvement.
Says Wagstaff: “This not only results in faster travel times but also in a safer and less stressful work environment, while minimising the impact on other drivers.
“It is no exaggeration to say that emergency vehicles arriving on the scene quicker or delivering sick patients to hospital faster can be a real life-saver. In addition, there is no need to use the sirens simply to activate the EVP system – which is beneficial to both the surrounding residents and a patient in an ambulance.”
The solution has been designed to be expanded and could also be used to aid the passage of other vehicles such as police cars and buses while temporary installations could be used for VIP escort vehicles, defence convoys and abnormal or dangerous goods loads.
Currently the system only supports Streams ‘native’ traffic signal management but Transmax says the architecture caters for the use of other traffic light systems and it is discussing potential implementations with partners.
Wagstaff concludes by saying: “This technology could certainly help authorities in many cities around the world reduce journey times for selected vehicles and also cut the number and severity of collisions between those vehicles and normal motorists.”
Mind the wake
The Wake Effect is a discernible increase in vehicle accidents after an emergency vehicle has passed by. Studies estimate such accidents occur at a rate four times higher than those experienced by the emergency vehicles and occur as out-of-position motorists move back to the appropriate lane for their journey.
While there is no data from the Queensland trial, Transmax says its EVP system should significantly reduce Wake Effect accidents as it minimises the need for drivers in stationary queues to move over to make way for the emergency vehicle.
“Drivers only have to draw on their own experience to know how much easier and less stressful it is to move out of the way of an emergency vehicle in moving traffic than when everything is queuing at the lights,” says Wagstaff.
Despite the lights and sirens, accidents between the motoring public and emergency vehicles on their way to/from the scene of an incident are relatively frequent. Figures from various sources indicate that road accidents are the second most frequent cause of death for on-duty fire fighter fatalities and that more than 90% of ambulance and fire engine accidents occur when the lights are on and the sirens wailing. Other studies indicate that the majority of ambulance accidents occurs when making turns or when broadsided at an intersection.
In an emergency situation such an accident has the potential to be a double tragedy with loss of life at the accident and the delay in getting to the original incident can be fatal for the victim or victims. After the accident the emergency fleet is one vehicle down which can have serious consequences and there are significant repair or replacement costs. With the imposition of emergency travel times adding further urgency to the need to attend a fire, accident or stricken individual and the traffic in many cities getting heaver, all the ingredients are in place for this trend to continue.
While, for obvious reasons, few would want to see emergency vehicles prevented from passing traffic lights during the stop phase, all would welcome moves to reduce the frequency of accidents that occur when they do. So in an effort to both minimise travel times and the potential for emergency vehicle accidents, the government of Queensland, Australia, is working with local ITS specialist supplier
The system automatically manages traffic signals before and after an emergency response vehicle passes the intersection. Essentially, the system interrupts the normal traffic light sequencing to turn the lights to green ahead of emergency vehicles and, more importantly, set the signals for the crossing traffic to stop. The resulting ‘green wave’ reduces both the emergency vehicle’s journey time and the potential for it to be involved in accidents at signal-controlled intersections.
Transmax says that while other systems can provide similar green wave functionality they typically require additional hardware either in the vehicles or at the signals. The aim of the Queensland project was to provide an intelligent EVP solution without the need for additional hardware in the vehicles or signals and without increasing the work load complexity for front-line officers. The subsequent EVP system being trialled in Queensland works without any specialist hardware in the vehicles or at the traffic signals and without any modifications to front-line officer operating procedures.
“Utilising the existing systems avoids the additional cost and complexity of installing additional equipment in the emergency vehicles,” Jason Wagstaff, chief operating officer with Transmax, told
The EVP system was delivered through a partnership between the
The Department of Community Safety developed the part of the system used to track the location of ambulances and fire emergency vehicles. This automatically starts working once the crew responding to an emergency call activated the warning lights (it is not necessary to use the sirens to trigger EVP). All tracking information is obtained from the mobile data terminals already installed in emergency vehicles.
Using computer-aided dispatch, GPS and traffic management technology, the EVP system not only determines the position of the vehicle but its trajectory and speed to calculate how long it will take to arrive at the next set of traffic lights. It then sends a message to the traffic control system to provide a green traffic signal in advance of the emergency vehicle’s arrival. Depending on when in the cycle the vehicle is expected to arrive at the intersection, the system either changes the sequence or extend/shorten the phases to ensure the emergency vehicle encounters a green light.
To handle the on-demand change required by the EVP system, Transmax developed a version of its Streams traffic light control software that accepts dynamic interventions while minimising the impact on other traffic. The revised system maintains pedestrian clearance protection, live monitoring at traffic management centres and user-configurable recovery algorithms.
The system operates fully automatically, although it also provides monitoring information to allow human intervention if an operator needs to override the system if for example an unintended queue builds up at the intersection. Wagstaff says this is ‘only expected to be used in very rare cases, and has not been experienced to date.’
A pilot deployment of the system was implemented in November 2012 in the city of Southport (population around 30,000), on the Gold Coast of Queensland. In total 20 emergency vehicles (10 ambulances and 10 fire engines) are participating in the ongoing trial encompassing 50 of Southport’s main intersections.
Preliminary results to date shows the EVP system is successfully detecting and providing a green wave for approaching emergency vehicles with their warning lights and sirens activated. Once the emergency vehicle has passed the system reverts to its normal sequencing and timing.
The emergency services in Southport respond to more than 100 incidents per week and preliminary results show the EVP-enabled vehicles benefit from more than 600 green traffic lights every week. Initial analysis indicates that travel times along major routes have been reduced by between 10% and 18% resulting in improved response times.
“While emergency vehicles can legally cross red lights normal motorists cannot so some of the improvement is due to it being easier for other drivers ahead of the emergency vehicle to get out of the way,” says Wagstaff. “Because the lights are green when the emergency vehicle approaches, it also reduces the number of unpredictable reactions by drivers in traffic queues at red traffic lights attempting to move out of the way.”
In reducing the number of times an emergency response vehicle needs to cross intersections against a red traffic light during the trial, the Department of Community Safety says “emergency responders using the system indicated a significant improvement in perceived safety.” It adds that as it does not have enough data to reasonably quantify the improvement.
Says Wagstaff: “This not only results in faster travel times but also in a safer and less stressful work environment, while minimising the impact on other drivers.
“It is no exaggeration to say that emergency vehicles arriving on the scene quicker or delivering sick patients to hospital faster can be a real life-saver. In addition, there is no need to use the sirens simply to activate the EVP system – which is beneficial to both the surrounding residents and a patient in an ambulance.”
The solution has been designed to be expanded and could also be used to aid the passage of other vehicles such as police cars and buses while temporary installations could be used for VIP escort vehicles, defence convoys and abnormal or dangerous goods loads.
Currently the system only supports Streams ‘native’ traffic signal management but Transmax says the architecture caters for the use of other traffic light systems and it is discussing potential implementations with partners.
Wagstaff concludes by saying: “This technology could certainly help authorities in many cities around the world reduce journey times for selected vehicles and also cut the number and severity of collisions between those vehicles and normal motorists.”
Mind the wake
The Wake Effect is a discernible increase in vehicle accidents after an emergency vehicle has passed by. Studies estimate such accidents occur at a rate four times higher than those experienced by the emergency vehicles and occur as out-of-position motorists move back to the appropriate lane for their journey.
While there is no data from the Queensland trial, Transmax says its EVP system should significantly reduce Wake Effect accidents as it minimises the need for drivers in stationary queues to move over to make way for the emergency vehicle.
“Drivers only have to draw on their own experience to know how much easier and less stressful it is to move out of the way of an emergency vehicle in moving traffic than when everything is queuing at the lights,” says Wagstaff.
