Dallas PD’S secret weapon
Although Dallas has been working for many years to increase the number of alternative fuel vehicles in its 6,000-vehicle fleet to reduce ozone-harming emissions, it has been a challenge to go green with the marked police vehicles. There are more than 1,000 marked police cars in the fleet, and the engines have to idle for long periods of time to power the emergency equipment.
In March 2009, the Dallas Police Department (DPD) began to study an anti-idling device that promised to store enough excess power from the alternator while the vehicle was running to operate all of the police equipment for at least four hours after the engine was turned off. The device from Austin, Texas-based Energy Xtreme was mounted in the trunk of one of the department’s fully equipped Dodge Chargers. Officers tested the vehicle to determine the effects of the added weight and found that it did not change the way the vehicle accelerated, stopped or handled in turns. After one month of hard driving, there were no negative effects related to the system. The test vehicle was then given to another officer who was told to leave the emergency equipment on each time he turned the ignition off to test the longevity of the power supply. Even after leaving all of the emergency equipment on for several hours, the vehicle started right up.
During a continuous 30-day study, officers averaged 4.85 hours per day when the vehicle was not running while the system powered the emergency equipment. That resulted in 145.68 hours of emergency equipment use without the engine idling, which saved 3.64 gallons of gasoline per day. Using the fleet price of $2 per gallon of gasoline, the system saved $7.28 per day or $218.40 per month.
The device also reduced the vehicle’s carbon dioxide (CO2) emissions by 72.75 pounds per day (at idle, a Dodge Charger burns 0.75 gallons of gas per hour and generates 20 pounds of CO2 per gallon), and it reduced wear and tear on the engine the equivalent of 169.75 miles of actual driving per day (each hour of idle is equivalent to 35 miles of driving). Pleased with the results, DPD is seeking grants to place the systems in at least 125 full service police cars.
Project: Anti-idling device test in police cars
Agency: Police Department
Vendor: Austin, Texas-based Energy Xtreme
Date: Spring 2009
Lt. Dale Barnard, fleet manager for the Dallas Police Department