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Michigan State Police 2010 Patrol Vehicle Tests
Each year since the 1978 models, the Michigan State Police has tested a variety of police package (pursuit capable) patrol vehicles. These annual tests include acceleration to 100 mph, absolute top speed, braking from 60 mph after brake warm-up, road racing course lap times, an ergonomic and communications installation review, and EPA fuel economy ratings.
The acceleration, top speed and braking phases are conducted at Chrysler’s Proving Grounds near Chelsea, MI. The vehicle dynamics testing is performed on the 2.0-mile road course at Grattan Raceway near Grand Rapids, MI. Of the 2010 models, the MSP tested six police package sedans and two police package 2-wheel drive SUVs.
The MSP did not test any special service package (not intended for pursuit) vehicles like the Explorer, Expedition, Suburban or 4x4 Tahoe. And even when these special service package vehicles were tested in the past, they were not run on the Grattan road course. This is to emphasize that the special service package vehicles are not designed for, nor intended for, emergency or pursuit driving. Only the emergency-driving, pursuit-capable vehicles, identified as such by the respective carmakers, undergo MSP testing.
2010 Police Vehicles
The police package sedans included the 4.6L V-8 RWD Ford Crown Victoria Police Interceptor (CVPI) with the 3.27 axle ratio, and the same car with a 3.55 axle ratio. Production of the Ford CVPI will stop after August 2011. An announcement of Ford’s big replacement is expected in early-2010. While all CVPIs can run seamlessly on E85, both of these CVPIs were powered by gasoline, i.e., E10 gasohol.
The RWD Dodge Charger was powered by both the 3.5L V-6 and the 5.7L V-8. Chrysler does not offer E85 Flex-Fuel in any of its police package vehicles.
The 3.9L V-6 FWD Chevrolet Impala was run in both E85 and gasoline versions. The only police package, pursuit rated SUV is the 5.3L V-8 2WD Chevrolet Tahoe, and the MSP tested both gasoline and E85 versions. The E85 powered cars are as fast as their gasoline-powered counterparts.
Nearly all of these police vehicles are carryover designs from 2009. For 2010, the 2WD Tahoe was upgraded to a 6-speed automatic trans for both better fuel economy and better performance.
The acceleration tests have maximum times allowed to reach 60 mph, 80 mph and 100 mph. The score for the event, however, is based on the zero-to-100-mph times. The tests are conducted slicktop, with no spotlights and with two troopers on board.
Of all the 2010 models, for the fifth year in a row the fastest-accelerating was the HEMI®-powered Dodge Charger. The Charger 5.7L V-8 reached 60 mph in 6.0 seconds. The HEMI Charger took just 14.2 seconds to reach 100 mph. In comparison, all the rest of the V-6 and V-8 sedans reached 100 mph in 22 to 23 seconds.
How does the acceleration compare among the two V-6 Impalas, the V-6 Charger and both axle versions of the V-8 Ford CVPI? The acceleration to 60 mph is just about the same. All these vehicles hit 60 mph in the 8-second bracket. The 3.55-geared Ford CVPI was the fastest sedan to 100 mph, followed by the V-6 Charger, the V-6 Impala and finally the 3.27-geared Ford CVPI. The police package 5.3L 2WD Chevy Tahoe with the new 6-speed actually got to 100 mph a half second faster than any of these sedans.
The second MSP test is top speed. At the end of the last acceleration run, the MSP troopers continue to accelerate the car around the 4.7-mile oval. The highest speed recorded anywhere on the course is the top speed of record. All police and special service vehicles are electronically speed limited but not all vehicles actually reach that preset, limited speed.
The HEMI Charger, of course, had the highest top speed, which was limited to 146 mph (an option on the HEMI Charger electronically limits the top speed to 132 mph). The 3.9L Impala was close behind at 139 mph, while the V-6 Charger was close behind that at 137 mph. The 2-wheel drive Tahoe reached 133 mph. The 3.27-geared CVPI ran 129 mph, while the 3.55-geared Ford CVPI is limited to 120 mph for reasons of driveshaft harmonics.
A side note on these top speed tests: The police department may not see the same top speeds from the in-service car as these cars achieve during testing. The fully upfitted patrol car weighs much more than these cars as tested. The addition of spotlights and lightbars adds aerodynamic drag, as does the addition of a front push bumper.
In some cases, depending on the extra weight and aerodynamic load, the car may or may not shift into the gear producing the most top speed, or may select a certain gear, hit the engine rpm limiter, and shut off without upshifting. If your department has a specific top speed the vehicle must reach, put it in the bid spec.
The MSP braking protocol involves two 90-mph, full-pedal stops to warm the brakes, followed by six 60-mph full-pedal stops for score. After a heat soak period, these two 90-mph and six 60-mph stops are repeated. The best 10 out of 12 stops from 60 mph are averaged for the final deceleration rate. This braking rate is converted to a projected stopping distance from 60 mph.
The best braking performance, now five years in a row, came from the Dodge Charger. The V-6 Charger stopped in just 138 feet, and the V-8 version stopped in 143 feet. This is very important because the brake pad compounds for the police Dodges were changed for 2008 to give longer pad life. Dodge has increased brake pad life without affecting braking performance. The Ford CVPI, 2WD Tahoe and V-6 Impala all stopped between 144 and 146 feet.
The Grattan Raceway is a 2-mile, 13-turn, road-racing course with a 3,200-foot front straightaway. By the end of the straight, the 250hp Ford CVPI, for example, reaches 110 mph. The course also has a number of twists and off-camber turns. On some parts of the track, the cars nearly become airborne, while on other sections of track the suspension almost completely bottoms out. Each car is driven for five laps by four different MSP troopers from the Precision Driving Unit.
On the road course, the fastest police package vehicle was the HEMI Charger. The V-8 Charger was more than 3 seconds quicker than the next closest car, which was the V-6 Charger. With overall lap times around 1 minute, 40 seconds, the time interval between the HEMI Charger and the other sedans works out to a 17 car-length difference. A full second behind the V-6 Charger were two Ford CVPIs, and two seconds (or 10 car-lengths) behind the two Fords were the two V-6 Impalas and the two 2WD Tahoes.
Again, special service package vehicles, such as the Ford Explorer, Chevrolet Tahoe 4x4 and Ford Expedition are not tested on the road course. This, in addition to clear and frequent written disclaimers from each manufacturer, emphasizes that these vehicles are not intended for high-speed, pursuit-style driving.
The Michigan State Police bases its fuel economy rating on the EPA City mileage results. Fuel economy matters now more than ever. Because fuel economy is a tangible cost, unlike acceleration to 100 mph, for example, some fleet managers consider this operating expense on equal footing with the initial expense of the vehicle. They are not going to spend a $0.15/gallon difference on a car that runs on premium fuel. Yet selecting a patrol vehicle with a 1.7-mpg difference in mileage is (cost-wise) the same as selecting an engine that runs on premium fuel. Expect 15% to 20% less mileage when running on E85 ethanol.
Because fleet managers divide police cars into so many categories, it is impossible to identify any one car as a “winner” based on the NIJ-funded MSP tests. Across the nation, fleet bid categories are subdivided into FWD and RWD, V-6 and V-8, etc. The “winning” car, the car with the best overall performance, may be the best V-6 powered sedan, or the best RWD sedan, or the best V-8 RWD sedan.
If some of the artificial bid distinctions are removed and instead the term “police package sedan” is used, a winner in sheer vehicle performance is obvious. The Charger V-8 has the fastest acceleration, the highest top speed, the quickest road course times and the shortest braking distances.
For their part, regardless of vehicle platform, the MSP is careful to point out that these tests (the minimums, the maximums and the category weights) are all designed for the way the MSP uses its patrol vehicles. Other departments will certainly use their vehicles in different ways, and this should put a different emphasis on the test results.
The MSP weighs the six test phases to suit the needs of a state police or highway patrol. The needs of city and county law enforcement agencies are probably very different. While subtle changes have taken place from time to time, the MSP typically weighs the tests at 30% for the road course, 20% for acceleration, 20% for braking, 15% for top speed, 10% for ergonomics and 5% for fuel economy. These numbers are plugged into a bid adjustment formula available at the National Law Enforcement and Corrections Technology Center (NLECTC) Web site.
Different weightings may be selected. For example, an urban department may want to emphasize fuel economy, ergonomics and braking while deemphasizing road course, acceleration and top speed. Because most bids are close, this change in weighting may point to a different police vehicle as providing “the most bang for your buck.”
Published in Law and Order, Nov 2009
Rating : 7.0
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