Hendon Publishing - Article Archive Details
2008 Los Angeles County Sheriff Vehicle Tests
Each year since 1974, the Los Angeles County Sheriff’s Department has conducted performance and fuel economy tests on police vehicles. With a total square mileage about the size of the state of Connecticut, Los Angeles County offers widely diverse operating conditions ranging from traffic-clogged urban streets, winding mountainous roadways, scorching deserts and high-speed freeways.
In comparison with the annual vehicle tests performed by the Michigan State Police, the Los Angeles Sheriff testing program places less emphasis on top speed and high-speed handling and more attention on urban handling, braking issues, and on mechanical reliability issues.
The current LASD program dates back to the early 1970s, when the department took it over from the Los Angeles Police, which began testing police vehicles in 1956! The current testing actually involves both the LASD and the LAPD as both agencies supply EVOC driving instructors to help evaluate the vehicles.
While there have been no major changes in any police vehicle over the past few years, and only minor changes to the Dodge Charger and Magnum brakes since last year, some interesting observations were made during the 2008 vehicle tests. This year, we are seeing wider acceptance of E-85-compatible vehicles. Ford’s Crown Victoria Police Interceptor is capable of operating on either gasoline, E-10 or E-85. Chevrolet’s Impala and Tahoe come in E-85 versions. For track testing purposes, the CVPI and E-85 versions of the Impala and Tahoe were run on E-85. However, during the fuel mileage tests, the Ford CVPIs were operated on gasoline. (The E-85 vehicles were not tested for fuel mileage).
Preliminary Handling Test
All vehicles, regardless if they are police package (pursuit-certified) or special service package must undergo the Preliminary Handling Test. This is a 1.57-mile high-speed driving course laid out at the Los Angeles County Fairgrounds “Fairplex” Complex. Each vehicle is driven eight laps by each test driver. Four test drivers are used for each vehicle, for a total of 32 laps. The average speeds of the pursuit-certified vehicles on this high-speed course were between 65 and 70 mph.
Both the fastest and slowest laps are automatically eliminated, and the remaining six laps are averaged. Each driver also subjectively evaluates each vehicle at the end of this phase. Vehicles that are rated as “unacceptable” are disqualified and are not allowed to participate in further testing.
The fastest police vehicle during on the Preliminary Handling Test was the 5.7L Dodge Charger, followed closely by the 5.7L Dodge Magnum. A little over 6 seconds separated the fastest (5.7L Charger) and slowest (Tahoe) times. Of the police sedans, the difference between the 5.7L Charger and the E-85 version of the V-6 Impala was a little over 4 seconds.
Immediately after the Preliminary Handling Test, the brakes are tested. This simulates actual operating conditions within police service, such as after an emergency run or pursuit situation. This also makes this brake test the hardest, most severe brake test performed by the police community. All of the brake testing was conducted in the same area of a smooth portion of the asphalt track surface, thus maintaining the same coefficient of friction during the testing.
The test vehicle is accelerated up to a speed of 80 mph, and the brakes are applied to maintain a deceleration rate of 22 fps2 without ABS activation. This test is repeated three more times. The vehicle is allowed to sit stationary for five minutes, allowing the brakes to cool down.
After the cool-down, the vehicle is accelerated to a speed of 60 mph and is decelerated at a maximum rate, just short of Antilock Brake System (ABS) activation. After a two-minute cool-down period, the procedure is repeated. The vehicle is then accelerated to 60 mph and the vehicle is stopped to simulate a “panic-stop” with ABS activation.
Any malfunctions (fade or pulling) are investigated to determine the cause. If the cause is correctable, then the vehicle is allowed to be repaired and retested. If it appears that the defect is a result of engineering or design, then the vehicle is disqualified from further testing.
The police sedan with the best brakes this year was the Dodge Magnum 3.5L V-6 with a 154.2-foot average stopping distance. Mere inches behind was the 5.7L Dodge Charger, then the V-6 Charger, then the Ford CVPI. The change to improve pad wear on the Charger and Magnum clearly did not affect overall braking performance.
A VBOX Datalogger, a GPS-based recording device, recorded acceleration times at all speeds up to 100 mph. Standing-start, ¼-mile acceleration is also measured. Unlike the Michigan State Police vehicle tests, the maximum top speed for the vehicles was not tested by the LASD.
The police sedan with the fastest acceleration to 60 mph and to 100 mph was the 5.7L Dodge Charger with times of 6.2 seconds and 14.6 seconds, respectively. The 5.7L Dodge Magnum was just a tick behind. These two 5.7L Dodges were 5 seconds ahead of the closest competitor to 100 mph.
The final test of pursuit vehicles is the Pursuit Course. This is limited to vehicles that are rated as police package (pursuit certified) by the vehicle’s manufacturers. Special service package vehicles are not tested in this phase. This is a 2.45-mile course that simulates a pursuit situation within an urban environment, consisting of a maze of twisting right- and left-hand turns, along with obstacles littering the roadway. The speeds on the city street simulation course average between 31 and 35 mph.
Two test drivers are used to evaluate each vehicle. Each driver completes two laps around this course. A vehicle is deemed unacceptable if it cannot complete the four-lap course in less than a combined time of 4 minutes, 45 seconds. Before participating in the Pursuit Course, at their option, the vehicle representatives were given the opportunity to rebuild the brake systems, but this year, none of the manufacturers exercised this option and went directly on to the Pursuit Course.
The fastest sedan on this phase was the 5.7L Dodge Magnum followed by the V-6 Charger and Ford CVPI. All test vehicles met the LASD maximum lap time requirement.
Drivers noted the Impala had a slight amount of understeer and brake fade. They commented that this vehicle had a slight to moderate amount of understeer, body lean and bounce during the turns, which was controllable. Some brake fade was noted, however, the brakes performed consistently. They also commented that the engine produced excellent power throughout its power band. The drivers and evaluators gave the Tahoe high praise for driver comfort, i.e., legroom, visibility and ease of reaching controls.
Both the 5.7L HEMI®-powered Charger and Magnum demonstrated impressive performance and braking with one test driver commenting; “This is the gold standard of police service brakes.” The Hemi-powered version, however, is 200 pounds heavier than the 3.5L V-6, with most of the weight in the front. This affects handling. The test drivers agreed the V-6 versions were better balanced in handling and breaking, as well as being easy and forgiving when driven “to the limit.” A couple of the drivers commented that the Hemi versions can be a “handful” when driven hard.
Little has changed on the 2008 Ford CVPI, which got the usual got high marks for handling, power range and shift-points. The drivers noted only a minimal amount of bounce and lean. They did notice some brake fade toward the latter portion of the Preliminary Handling Test. However, the fade was minimal with the brakes slowing the car at an acceptable rate of deceleration.
Admin Fuel Economy
The Fuel Efficiency Test simulates real-world conditions and is conducted over a 100-mile course. In the past, one test driver drove each vehicle through the course during lighter traffic conditions. The current protocol is to run each car through this course twice, with different drivers, during peak (rush-hour) traffic conditions. The course is divided equally with urban, suburban and freeway driving conditions. Standard pump gasoline was used, even on E-85 compatible versions. The vehicle’s headlights and air-conditioning are turned on, and the transmissions are placed in the “overdrive” position.
The vehicles are driven in a normal manner, i.e., the vehicles are neither driven gently nor driven for maximum performance. By definition, this test simulates the mileage that a detective or administrative vehicle would obtain. Experience shows that a marked patrol unit would obtain about 60% to 70% of these mileage figures.
The police sedan with the best gas mileage under these test conditions was the 3.9L Chevy Impala with a 17.6-mpg average. The 3.5L Dodge Charger was close behind with a 17.5-mpg average.
The LASD rates space utilization and human factors in an evaluation conducted by four uniformed deputies who drove the vehicles over the 100-mile loop used to measure fuel consumption. The evaluations are conducted separately, and the ratings are averaged to minimize any individual prejudices for or against any of the vehicles. Vehicles are evaluated for general suitability and efficiency as a patrol vehicle, or other specific functions that the LASD may require.
Mechanics who service the department’s vehicles also evaluate each vehicle for ease of routine maintenance and service as well as the ease of repair of various vehicle components.
Finally, the ease of installation of communications equipment (two-way radios, and mobile data computers) is rated. The radiated output of this equipment must not interfere with the operation or performance of the vehicle, nor may the vehicle cause excessive radio interference. Technicians from the Los Angeles County Sheriff’s Department Communications and Fleet Management Bureau conduct this evaluation.
Among the sedans, the Charger and Magnum received the highest ratings for the front-seat roominess. The Magnum and Ford CVPI were judged the highest for the instrument panel and driver controls. The Ford CVPI got top honors for overall visibility and mirrors. The Ford CVPI also earned top honors for the rear-seat roominess. The Magnum, predictably, got the highest ratings for trunk space. The Impala was rated the best overall for the precision maneuvers and parking phase. Overall, with all six of these categories averaged, the top ergonomic rating among sedans went to the Dodge Magnum.
While the Los Angeles County Sheriff’s Department does not recommend any specific vehicle(s) or tire(s), their test protocol and results are published annually. For further information on the program, contact the Communications and Fleet Management Bureau at (323) 267-2511.
John Bellah is the technical editor of Police Fleet Manager. He is a corporal with a Long Beach, CA area police department and a 30-year police veteran. He can be reached at firstname.lastname@example.org.
Published in Police Fleet Manager, Mar/Apr 2008
Rating : 9.0
Click to enlarge images.