Vehicles

Vehicle Selection, Maintenance and Replacement 4x4

Patrol Vehicle Selection:

Law enforcement vehicles are used in a much more demanding environment than the average civilian vehicle. A patrol vehicle normally runs every day for a minimum of 10 hours per day and drives hundreds of miles. The vehicle may idle for an hour to power the warning lights at an accident scene and then quickly respond to a call where the deputy may be required to use heavy acceleration, cornering and braking. This type of operation is very stressful on a vehicle and requires special electrical, braking, transmission and engine systems. Patrol vehicles must be big enough to place a containment cage into them, have the capability to drive in extreme weather conditions, be fast enough to respond to serious incidences and have the capability to handle hard braking and cornering. All three domestic auto makers (Chevy, Ford, and Dodge) build vehicles that are made to handle the stresses of law enforcement. These vehicles are not sold to the general public and are only available to law enforcement type agencies for a limited time each year.

There are many factors that go into the selection of a patrol vehicle.  We emphasize lifecycle cost and vehicle functionality. Lifecycle cost refers to overall cost to operate the vehicle and includes purchase price, fuel economy, resale value, and maintenance cost. Function refers to how well the vehicle performs and takes into account vehicle downtime, handling in extreme weather conditions, ease of operation, visibility and other safety factors.

CarIn past the Sheriff’s office has purchased some Chevy Tahoe SUVs because they meet the functionality demands of the department and the overall lifecycle cost was the same as  smaller rear wheel drive sedans and in some cases the cost to operate the Tahoe was less than operating other vehicles. In fact an independent study conducted by Vincentric in 2010 shows that the Chevy Tahoe had an overall lower cost of ownership than the Chevy Impala, Ford Crown Victoria and Dodge Charger law enforcement vehicles.

In 2014 DCSO selected the Ford AWD SUV Interceptor as its patrol vehicle. This vehicle is an AWD pursuit rated crossover SUV with 3.7L V6 engine. This vehicle was compared to the Dodge Charger 3.6L V6 engine RWD, the Chevy Caprice 3.6L V6 engine RWD, and the Chevy Tahoe V8 engine RWD.  At the time we conducted the test the Ford Interceptor SUV and Sedan was the only AWD pursuit rated vehicle on the market.

Four-wheel drive Tahoes and/or All Wheel Drive SUV’s are generally more effective in Douglas County because it is primarily rural and mountainous.  Law Enforcement is expected to respond to life safety calls for service regardless of terrain, obstacle, or weather.  In rural areas emergency assistance is generally less available and has to travel greater distances than in urban areas.  Law enforcement vehicles must have adequate space to carry  extra emergency, technical and procedural equipment, supplemental vehicle mounted weapons, and emergency management supplies (commander’s vehicles) because additional help will probably not arrive quickly when time is of the essence.

Douglas County Fleet services did an analysis and found:

  • Re-Sale Value: in most cases the cost to operate a front wheel or rear wheel drive full size sedan is equal to, or higher than the operating cost of an all-wheel drive SUV because of re-sale value.  After 6 years of law enforcement use on a 4 door sedan, the county is only able to re-coup about 8% of the original purchase price. However, 4 wheel drive and all-wheel drive SUV’s recoup about 45% of their original purchase price. In most cases the County will receive $10k to $12k more in re-sale value for a SUV compared to a sedan including the up-front purchase cost because the SUV is normally $3k to $5k more than a sedan.
  • Maintenance Cost Per Mile: Maintenance cost between these vehicles is virtually a wash, and in some cases we have found the Dodge Chargers incur a higher cost per mile and higher downtime rates than the SUV. The heavier components in an AWD SUV vehicle stand-up better in a law enforcement environment compared to sedans. The SUV maintains a higher reliability rate than the sedans.
  • Fuel Cost: Todays engines that are placed in the SUVs and Sedan pursuit vehicle are high-output V6’s, but sedans typically get 10% better fuel economy than the SUVs.
  • Functionality: With operating cost being a wash between sedans and SUV’s the selection of patrol vehicle comes down to function.  AWD  SUV’s have better handling in extreme weather conditions, better visibility and provide the room needed for computer mounts and weapon locks in the patrol vehicle. Additionally, standardization of the patrol fleet can be accomplished because the SUV can accommodate the different vehicle configurations required by the Sheriff’s Office. An SUV can be a K-9 vehicle, a command vehicle, a standard patrol or an undercover vehicle.  AWD vehicles handle in the same manner as the rear wheel drive vehicles the sheriffs’ office trains on for pursuit.

Douglas County uses the information provided below to calculate vehicle replacement timing:

  • Age Factor – 1 year of age is equal to 1 point and each month is equal to 1/12 of a point
  • Maintenance Factor – When 10% of the vehicle purchase price is spent on maintenance 1.5 points are allocated
  • Utilization Factor – Every 15,000 miles, or 1,200 hours equals 1 point
  • Use Factor“General Use” (on improved roads) equals 1 point, “Work Use” (trucks & some off road) equals 3 points, and “Severe Use” (patrol, off road, construction) equals 5 points
  • Condition Factor“Outstanding” equals 1 point, “Clean” equals 3 points, “Average” equals 5 points, “Rough” equals 7 points, and “Damaged” equals 9 points
  • Downtime Factor – 1% of downtime equals 1.5 points 

Douglas County uses the replacement point scale noted below:

  • < 25 points                  Do not replace
  • 26 – 31 points             Unlikely to replace – unless maintenance/downtime is 7 or higher

and condition factor is 7 or higher

  • 32 – 37points              Early replacement candidate
  • 38 – 43 points             Optimal replacement time – optimal resale value – less than 10%

Of useful life left

  • 44 – 50 points             Overdue replacement
  • 51 points                     Critical to replace immediately 

Preventive Maintenance:

Base preventive maintenance is performed on patrol vehicles every 5,000 miles at a cost of $123.00 and 1.24 hours of a technician’s time.  All fluids and parts meet or exceed OEM requirements.  It includes:

  • Road tests before & after to test handling, braking and overall vehicle operation
  • Oil is exchanged and all other fluids are topped off
  • Inspection of under carriage, suspension exhaust and driveline
  • Tires are rotated and pressure is checked
  • Brakes are inspected and measured with the tires off
  • Oil filter is replaced, air filter is inspected and replaced if needed
  • Other checks include: lights, heater, AC, & other operating systems for proper operation 

Other components are inspected depending upon make and model.  Higher levels of maintenance are performed at various intervals, i.e. replacement of transmission fluid, spark plugs, etc. when specified by the manufacturer.

Douglas County Sheriff

Justice Center

4000 Justice Way
Castle Rock, CO 80109
Phone: 303.660.7505

Office Hours

Monday through Friday
8:00 a.m. – 5:00 p.m.


Highlands Ranch Substation

9250 Zotos Drive
Highlands Ranch, CO 80129
Phone: 303.784.7800

Office Hours

Monday through Friday
7:30 a.m. – 5:30 p.m.


Directions »