The ordeal of drivers wasting their time at Hashomrim Junction in the north is typical of the basic flaw in Israel’s traffic-light system. Every morning gridlock plagues the intersection as drivers turn south from Route 75 onto Route 722. Those lucky motorists — representing the lighter traffic load — get the longer green light.
The cause of the problem at this crossroads between Nazareth and Haifa is simple and disturbing: Israel’s traffic-light system gives preference to cars on wider routes. So a road with a two-digit number will have a longer green light than one with three digits, regardless of the actual traffic load.
Israeli traffic lights have many arbitrary features that cause problems in cities as well. Sometimes the green light is too short to handle the demand, turning red before the first driver has lifted his eyes from his smartphone.
Sometimes the situation is truly absurd, as experienced by anyone traveling on Jabotinsky Road between Route 4 and Tel Aviv on Saturdays and religious holidays. The long waiting times at lights in the Bnei Brak area are puzzling because all entrances to that ultra-Orthodox city are closed.
These two examples highlight a nationwide phenomenon. Every driver probably has a light he particularly hates.
As in many countries, roads in Israel are chock full of cars, so traffic lights have the complex task of handling heavy traffic in all directions. The technology now available in Israel and most of the world leaves something to be desired.
The current system is based on fixed cycles with limited flexibility. Underground sensors tell the light’s control system how many cars are waiting; they also say when approaching heavy traffic requires a longer green light.
The division of green lights is updated from time to time according to pre-set schedules. On major routes, controllers from the National Roads Authority also intervene when necessary.
Still, the traffic-light system doesn’t respond well. Some experts estimate that 10 percent of the sensors are out of order at any given time, sometimes due to wires that have been gnawed on by rats.
So what can be done to improve vehicle flow at intersections? The physical solution is to separate traffic by building interchanges and getting rid of the traffic lights. But this is a very expensive step whose planning and execution takes years.
A technological solution is to place cameras or radar at intersections that would identify heavy loads from one direction and change the light cycle or channel the traffic as necessary.
The traffic-light industry thus is heating up ahead of pilot projects for new-generation lights planned by the roads authority and Haifa, Jerusalem, Kfar Sava and the Jezreel Valley Regional Council. The plan is to have one new system working at a not-too-busy intersection within a year.
The authority, responsible for 530 intersections, wants first to study the new system’s performance under less stressful conditions. The plan is to install many more systems by 2020.
Currently, only conventional technologies are approved for use as sensors at intersections. Because of safety considerations, any change in a traffic-light system requires approval by an interministerial committee headed by the Transportation Ministry. After pilot projects are completed, the committee will have to select a company in a complex regulatory process.
Anyone seeking to introduce smart lights needs funding from the Transportation Ministry. A conventional system at an intercity intersection costs up to 200,000 shekels ($57,000), depending on the complexity needed. A system based on radar or cameras is estimated to cost hundreds of thousands or even 1 million shekels when using the best technology available.
The companies supplying traffic-light systems in Israel include Menorah, IPI and R.S. Industries, which represents German industrial giant Siemens. Most of them plan to market new systems based on radar or image processing, looking for business as Israel upgrades its systems over the next few years.
Another innovative solution, much simpler and cheaper than other alternatives, is an algorithm developed in Israel that uses existing infrastructure for streamlining traffic at intersections. The algorithm monitors traffic using sensors embedded in the road, calculates traffic loads on the different approaches and gradually increases the green-light duration for the approach with the heaviest load at the expense of the one with the lightest. The goal is equilibrium between all the cars at the intersection.
The algorithm, which doesn’t require additional special equipment, was developed a few years ago by Ofer Hofman, the founder of Sital Technology. Hofman develops communications for transportation systems, satellites and warplanes. He has been integrating similar algorithms in his products for years.
These products are intended to develop learning systems that adapt to changing data. Hofman estimates that the integration of his system into existing traffic lights will cost 100,000 to 200,000 shekels for each intersection.
In a study, expert Elya Ben-Shabbat ran a simulation of this algorithm at a Haifa intersection; the algorithm significantly improved average waiting times for drivers. In one case, waiting times of eight minutes were reduced to less than three, with the green-light duration increasing over 21 cycles from 10 to 23 seconds, and drivers in the other direction hardly felt the difference.
The delicate adaptations achieved with this algorithm prevented new lines from forming in other directions. According to the study, each intersection will have to be individually planned according to its specific conditions.
Hofman’s algorithm has been patented in several countries. It has been approved by scientists and engineers at the Technion technology institute in Haifa. Hofman now plans to integrate it into a few pilot programs, but he says local councils and the roads authority haven’t yet managed to do so in a single traffic light.
Hofman and his associates also say vested interest groups are worrying about their livelihoods amid their plans to market their own products based on radar and image processing. Hofman says such systems are expensive to maintain and complicated.
“In any case, these systems make changes after congestion has developed, using a preplanned program,” he says. “This isn’t necessarily optimal for specific conditions at each intersection.”
Ido Dori, the deputy head of the Jezreel Valley Regional Council, is trying get government ministries to help alleviate the worsening traffic jams in the valley, including at Hashomrim Junction.
“After seeing Hofman’s algorithm, it’s clear that it’s required everywhere and here in particular,” he says. “We’d like to see the first upgraded traffic light here. I think it’ll be followed by hundreds more in Israel and abroad, saving us all many minutes every day.”
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