FLIR enables smooth intersection traffic flow in Utrecht, the Netherlands

ThermiCam thermal sensors from FLIR Systems have been deployed at a big signalized intersection leading from Utrecht to Amersfoort, the Netherlands. Based on heat energy coming from bicyclists and motorists, the cameras from FLIR can detect both types of road users and make a distinction between the two. The cameras pass down their detection information to the traffic lights and this way, a separate regulation for bicyclists and motorists is made possible, all the while both road users are sharing the same road space. The result of this installation is a smoother and more logical traffic flow at the intersection.

The province of Utrecht was looking for an efficient way to let the traffic at the intersection with the Utrechtseweg (N237) and Wilhelminalaan flow in a much smoother way. More specifically, the traffic authorities needed to find a solution to allow the traffic coming from the Wilhelminalaan and from the exit of the KNMI site (Royal Netherlands Meteorological Institute) to have sufficient green time to cross the Utrechtseweg based on presence information of vehicles. In order not to create any unnecessary waiting time at the intersection, the presence of cyclists should not generate green time. At that intersection, bicyclists can only turn left or right before the intersection area, not straight ahead. For this specific situation, a separate regulation for bicyclists and motorists was the best suitable solution. 

Integrator and installation company Imtech Traffic & Infra selected the ThermiCam thermal sensor for FLIR Systems to do the job. “For this specific project, we needed a solution that was able to efficiently detect bicyclists and neglect motorists at the same time,” says Guus Sluijsmans, traffic engineer and account manager sales at Imtech Traffic & Infra. “The ThermiCam sensor from FLIR Systems is the only solution I know that can efficiently make a distinction between bicyclists and motorists on the same traffic lane.” 

ThermiCam thermal imaging sensor

ThermiCam is an integrated thermalcamera and detector for vehicle andbike presence detection and countingat signalized intersections. ThermiCamdetects vehicles and bicycles at and nearby the stop bar. The intelligentThermiCam sensor will transmit itsdetection information over contactclosures or over IP to the traffic lightcontroller and will thus allow a moredynamic control of traffic lights. Thesensor picks up heat energy comingfrom the cyclists and motoristsand uses this to make a distinctionbetween the two. This way, greentimes can be adapted depending onthe type of road user.ThermiCam will also detect cyclistsand vehicles at night or when thesun is low, whether the road usersare moving or stationary. The thermalsensor can also be used to countcyclists, even when they are ridingin group. This functionality can worksimultaneously with the presencedetection functionality and uses thesame detection zones and regions.ThermiCam is a very interestingalternative for detection loops. In thecase of the Utrecht intersection, it waseven impossible to use detection loops,because the intersection’s differentroads connected on a bridge deck.In addition, today’s most commondetection loop solutions cannot makean efficient distinction betweencyclists and vehicles. Conventional, visible-light video cameras werealso not a good solution, becausedetection from these products is oftennot reliable at night and during hourswhen the sun is low on the horizon.

Vehicle and bicycle detection 

Vehicle detection 

Smooth traffic flow

The ThermiCam installations at theintersection along the Utrechtsewegserve two purposes. First of all, theymake sure that bicyclists receivesufficient green time for the trafficlights giving access to the bicycle lanesalong the Utrechtseweg. Second,they make sure that bicyclists do notgenerate green time for motoriststhat want to cross the Utrechtseweg.This set-up has already proven to bean effective way to minimize trafficblocking on the Utrechtseweg, andto maximize the traffic flow for thedifferent types of road users.“The ThermiCam bike and vehicledetection works perfectly, also inthe darker hours and in cold weatherconditions,” comments GuusSluijsmans. “We are happy to havefound an efficient detection solutionfor this difficult, mixed traffic situationand that we have been able tocontribute to a smooth traffic flow atthis intersection in the city of Utrecht.”