No one other than a patrol officer is better able to understand the vital role of a police vehicle in today's law enforcement. The wrong vehicle can affect officer morale, reduce efficiency and increase a department's operating costs appreciably.
Each year two agencies - the Michigan State Police and the Los Angeles County Sheriff's Department - test and evaluate police cars with a degree of thoroughness and accuracy that makes them the authorities on police vehicle performance.
This POLICE magazine report is primarily based on testing performed late last year by the Los Angeles County Sheriff's Department. The LASD Law Enforcement Vehicle Test and Evaluation Program, in addition to measuring vehicle performance, also utilizes test procedures to predict long-range vehicle reliability factors and other concerns that affect the vehicle purchase decisions of law enforcement agencies.
For example, to help determine long-range engine and component reliability, various measurements including the temperatures of engine oil, coolant, transmission fluid and power steering fluid are recorded under conditions that simulate patrol car duty on a hot summer day.
Kicking the Tires
LASD mechanics also evaluated each vehicle and rendered judgments on ease and cost of maintenance and repair. These evaluations took into account transmission or water pump replacement, as well as oil and filter changes and tune-ups.
And some non-mechanical issues were considered.
Technicians studied the difficulty of installing the emergency equipment - prisoner cages, shotgun racks, radios, sirens, and warning lights - and noted less than obvious factors such as the excessive radio interference some of this equipment can cause.
Ergonomics is one of the most important concerns for the patrol officers who have to ride in these cars, and the LASD testing accounts for the interior design of the vehicles. For example the evaluation team notes when the awkward placement of a control device could contribute to the cause of an accident. Beyond safety and convenience, these officers also rated the cars on comfort, knowing full well an uncomfortable vehicle will seriously affect morale over a more than 8-hour tour of duty.
Rules of the Road
For the 2002 model year LASD tests, the vehicles were divided into two categories, pursuit class and special service. Each vehicle was required to complete the "Preliminary Handling and Test Driver's Subjective Evaluation."
During this phase of testing, each driver completed eight laps around a 1.57-mile test track laid out in the parking lot of the Los Angeles County Fairplex in Pomona, California. This high-speed driving course consists of three straight stretches and three braking areas. Each car ran a total of 32 laps, and vehicles judged "unacceptable" were disqualified from further testing.
After the prelim, which is a good simulation of pursuit conditions, the brakes were tested. The drivers accelerated the vehicles to a speed of 90 mph, then applied the brakes. The goal was to maintain a 22-feet-per-second deceleration rate.
The deceleration rate test was repeated twice, and each vehicle was allowed to cool down for five minutes. Then each vehicle was accelerated to 60 mph, and the brakes were applied - just short of the ABS feature becoming active. This was repeated twice, and followed by a 60-mph panic stop (with ABS).
If any correctable failures were noted during the braking and deceleration tests, the vehicle was repaired and retested. If the failures appeared to be an engineering defect, the vehicle was disqualified.
The LASD does not record top speeds. However, the elapsed time and speed to complete each lap was measured, as well as the acceleration time to various speeds, including 0 to 100 mph.
Pursuit class vehicles receive a second evaluation on a "Pursuit Course." This course covers 2.45 miles, simulating a pursuit in an urban area. There are no straight-aways, and various obstacles are intermixed with various right and left turns. The Pursuit Course is also utilized in the tire tests, which include tires from several manufacturers.
Fuel mileage was checked by driving a predetermined 100-mile course. The course covers urban, suburban and freeway driving conditions, during which the cars were driven normally. Headlamps, radios, and air-conditioning systems were operated, simulating the mileage that a detective unit would tally under average usage. (As a point of reference, a marked unit's mileage is typically about 60 percent of this figure, due to the nature of its assignment - idling, low-speed, patrol, and emergency responses.
The LASD clearly states in its literature that different agencies have different needs. Its program does not recommend any particular make or model of vehicle. To obtain any additional information or to obtain copies of the complete test results contact:
Los Angeles County Sheriff's Department Fleet Management Unit
1104 N. Eastern Avenue Door #50 Los Angeles, California 90063