Turning the key off is the easiest thing to do and does not need any retrofits. Just a gentle reminder and a willing bus driver to honour the requests.

But other technology solutions do exist as well. DADA, is collaborating with Fleet Challenge Ontario, to pilot an idle-off technology to be used in Police cars and EMS vehicles that will automatically turn off the engines when parked for a period of time.

Other Technologies to Reduce Idling

School buses can be retrofitted with equipment that helps reduce idling. While some of this equipment is standard or optional on new buses, older buses most likely do not have it. Note:  this information is only as an aid to fleet managers and others concerned with bus idling, and it should not be viewed as an endorsement of any particular technology or product.

Heaters

Aftermarket auxiliary heaters can be used to warm up engines and passenger compartments in colder climates. This equipment runs off the school bus fuel tank or off electric outlets and includes a timer that can be programmed to automatically start the heating function. There are three types of heaters:

• Engine Block Pre-Heaters are used to heat the engine block for a warm start. Each block pre-heater uses only 1/2 cup of diesel fuel per hour as opposed to at least a half-gallon of fuel per hour of idling. Block engine pre-heaters cost approximately $1200 - $1500, installed. Some of the reported benefits of these heaters are lower emissions and fuel savings, longer engine oil life, less wear-and-tear on the engine, and relatively easy installation and maintenance. They can be used in remote yards or other situations where electrical block heaters are not practical or available to install and can be started by a timer, potentially saving time that would have been used to start and idle the buses.
• Compartment/Engine Block Heaters warm up the engine block and passenger compartments simultaneously while using an auxiliary heater. These heaters cost approximately $2300 - $2500 installed. The heaters use only one cup of fuel instead of the half-gallon of fuel needed to idle for an hour. These heaters are especially useful for nighttime-activity buses and buses that transport very young and/or special-needs children. In addition, the radiant heat keeps the windows from frosting or fogging — a safety concern.
• Electric Plug-in Block Heaters warm up the engine block by heating the engine coolant or oil. They are powered by electricity and are available in a range of voltages and watts, drawing between 1000 - 1500 watts per bus per hour. They include a timer that can automatically start or turn off the heater. A heater is mounted on the engine block of each bus and is plugged in when the bus is parked at the depot. Even in the coldest climates, engines will have a "warm start." Bus depots and garages can be designed or retrofitted to bring in the electrical service required. Such heaters usually cost less than $100.

Overhead Flashing Lights and Other Safety Equipment

• Some safety equipment can be run by re-wiring the circuitry in the bus. Some newer buses already have circuitry wired this way. The master switch for the overhead red flashing lights should be wired off the battery-positive side of the body solenoid (not the ignition side) so that it will have power at all times, even with the key in the “off” position. The wire terminals from the overhead flashing lights unit should be connected so that the complete system works with the key off and the door open. Check with the manufacturer of the overhead unit for more information on re-wiring the circuitry.
  Source: EPA