Frequent Questions

What is the difference between extended idling and normal idling? Is it possible to get distinct idling emission output for any vehicle type? Can this be done in the emission rate mode, or only inventory mode?

Extended idling is a distinct emission process defined as the overnight idling of long-haul trucks with sleeper cabs at truck stops and other locations during federally required downtime. During such idling periods, these engines experience unusual loads (televisions, air conditioning, fans, etc.) and higher than normal idle speeds.

MOVES also calculates idling emissions that occur during normal operation for all vehicle types. Sources of normal operation idling include stopping at traffic signals and railroad crossings, and idling during truck loading and unloading. These idling emissions are included in the results for the running emissions calculations.

The Project Scale in MOVES, when run in inventory mode, allows the user to define a link that contains only idle operation and get idle emission output. To do this, define the vehicle volume of the link as 1 vehicle and assign an average speed of 0 mph. In the link source input, you can specify the particular type of vehicle (e.g. passenger cars) with a fraction of 1 for the link. You can also include information about the age distribution, fuels, I/M program and meteorology. Since Project Scale runs are performed for one hour of a selected day type, month, and year, inventory output from the run will be in the form of grams per hour.

Doing a project-level run in emission rate mode will not give you idling emissions, since the idling operating mode is not reported separately. Each average speed and road type has its own driving schedules with an embedded estimate of idling time. The impacts of this type of idling are included in the exhaust running emission process along with the rest of vehicle operations.

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