Drivers beware. You might soon find yourself being pulled over by a policeman - and not because you have been suspected of posing a security threat or performing a traffic violation. If you are driving an old car, chances are you are being pulled over to have its gas emission levels measured. At the intersection near Liberty Bell Garden on a recent day where drivers are being pulled over for the highly efficient two-minute emissions check, the choke of the smog is palpable. Since last September, the municipality and the Environment Ministry have been measuring the levels of carbon monoxide and smog emitted by Jerusalem's 140,000 automobiles. And with good reason. Poorly tuned automobiles are one of the leading causes of air pollution. At the center of the joint operation between the municipality and the Ministry of Environment is a $70,000 mobile measurement machine donated by the Bracha Foundation. The apparatus uses light absorption technology to check the carbon monoxide (CO) emissions from diesel cars and employs yet another mechanism to measure the concentration of carbon monoxide emitted from benzene engines. Under the agreement worked out with the Bracha Foundation, a nonprofit group partly focused on environmental issues, the machine, which is hooked up to the inside of a van, is employed four or five days a week in various locations around the city. The ministry and the municipality have also agreed to keep it in commission for at least five years, evenly splitting the NIS 500,000 annual running costs. According to Nimrod Levy, the hazardous material and air quality coordinator for the municipality, approximately 700 vehicles are tested each month. Of these, 61 percent are diesel engine cars and 39% are regular benzene engines. "We test diesel engines more intensively than benzene engines because the type of carbon monoxide particles released by diesel engines is more dangerous to your health," Levy says. Passage or failure of the test is based on a sliding scale of the number of CO particles a car releases versus the year of its make, with newer cars being held to higher standards. Levy declined to identify which types of cars might be more prone to pollution problems, explaining that not enough statistics have yet been gathered. Out of the 2,127 diesel cars tested during the last four months of 2005, however, 16% failed the test and of the 1,334 benzene cars tested, 17% failed, Levy says. Incidentally, all 70 of Jerusalem's Egged diesel engine buses tested last month passed muster, which Levy attribute to Egged's use of buses that comply with the new European diesel standard. There are two common reasons cars fail the test: "dirty fuel" in the case of diesel engines - where low-quality fuel is illegally sold and put in the car and car owners fail to have their cars tuned regularly. For benzene car owners, test failure results in a 10-day grace period to have the car repaired and retested before a report is sent to the Ministry of Environment preventing a fine ranging anywhere from NIS 250 to NIS 2,000. Diesel engine owners, however, are out of luck. Failing the test automatically results in a report being sent to the ministry. "Owners of diesel engines can physically see the smog coming out the back of their car," Levy explains. "They know that there is a problem and have chosen not to do anything about it." This concept was not accepted easily by one driver who returned to the Liberty Bell Garden testing site to argue his case after his diesel car failed the test a few days previously. Armed with receipts from various gas stations stating that nothing was wrong with his car but a case of bad fuel, he demanded to have his car retested. Some shouting and arm-waving later, he left, having lost his bid. Molly Ben-Ari, assigned to give drivers documentation at the testing site, says often when drivers' cars fail the test they accuse the city of trying to scam them for money. Most of the reactions of drivers being pulled over at Liberty Bell Garden varied from mild annoyance at having their morning routines interrupted to the classic refusal to acknowledge that anything out of the ordinary might be happening. At least one driver with cellphone balanced in one hand and cigarette dangling in the other continues to pollute the air with noise and smoke while his car underwent its personal air pollution test. The car passed. Not everyone minds the interruption, however. One driver marvels at the efficiency of the three-man team, which has drivers back on the road in under five minutes. "It's really not a lot of time and it's an excellent idea, so I'm not bothered," he says. Rami Karan, heading the two-person technician team, says cars are profiled before they are pulled over, with older diesel engine cars receiving greater attention. Within a one-hour span, though, only male drivers are stopped. Karan insists that gender profiling is not at play and instead offers the explanation that "men are just more willing to drive bad cars than are women."