NOTE: This document is intended to answer commonly asked questions about N.J.’s idling restrictions, “Control and Prohibition of Air Pollution From Diesel-Powered Motor Vehicles”, N.J.A.C. 7:27-14 and “Control and Prohibition of Air Pollution From Gasoline-Fueled Motor Vehicles”, N.J.A.C. 7:27-15.
For a full copy of the regulations, see www.StopTheSoot.org.
1. Am I allowed to idle my diesel truck while I’m sleeping in it?
Beginning on May 1, 2011, only those vehicles with sleeper berths that have a model year 2007
or newer engine, or have been retrofitted with a diesel particulate filter, will be allowed to idle
past the three-minute limit but only while the driver is resting or sleeping in the sleeper berth.
An enforcement officer may need to confirm that there is someone sleeping in the sleeper berth.
Idling is not allowed to provide heat or air-conditioning for pets.
Drivers and trucking companies are encouraged to use alternatives to engine idling for
temperature control that will save fuel and maintenance costs such as alternate power units or
2. How long am I allowed to idle to warm up my diesel engine?
When the ambient temperature is below 25 degrees Fahrenheit, a motor vehicle may idle for 15
consecutive minutes when the vehicle has been stopped for 3 or more hours. Otherwise, idling is
limited to 3 minutes. However, most diesel engines take 3 minutes or less to warm up (consult
the engine manufacturer’s recommendations). Limiting idling will save fuel and money.
3. Will I get a ticket for idling while I am waiting for passengers to board my bus?
Idling is allowed for no more than 15 consecutive minutes in a 60-minute period while
passengers are actively loading and unloading buses only if the bus needs to run the heat or airconditioner
for passengers already on-board. However, buses cannot idle for extended periods of
time while claiming to be waiting for passengers, such as a tour bus on a layover waiting for the
group to return.
4. Are school buses subject to the 3 minute idling limit?
Yes, but school buses are encouraged to eliminate ALL idling except for when they are sitting in
traffic. School districts are encouraged to sign a No Idling Pledge, in which they agree to
implement practices to eliminate or reduce idling (see www.StopTheSoot.org). Because children
are especially vulnerable to the effects of diesel exhaust, drivers should turn off engines even
when loading and unloading students. Diesel exhaust from queuing school buses enter the
school buses behind them and often enter a school’s ventilation system where the entire school
population is exposed.
School vehicles that are transporting medically needy students are allowed to idle to reach the
temperature needed to meet the student’s medical needs. In these cases, the driver should have
documentation on-board that identifies the student and the necessary temperature requirements.
5. Are there exceptions to allow idling for more than 3 minutes?
Yes. Diesel vehicles whose primary power source (engine) is necessary for operation of
mechanical devices such as refrigerated trailers commonly called reefers, hydraulic lift gate
pumps, air leveling equipment, cherry-pickers, etc. Some turbo-diesel engines, especially newer
models, require approximately 3 to 5 minutes of idling to cool down the engine and avoid
damage. These vehicles will be allowed to idle for a length of time necessary for cooling as
determined by the engine manufacturer and set with automatic timers.
In addition to these situations, armored trucks are exempt from idling requirements for several
reasons. In order to assure the security of the cargo and drivers, these vehicles’ engines must be
on at all times. The windows of armored vehicles cannot be rolled down, which results in
temperatures inside the vehicle that can be harmful to occupants. Most armored vehicle
companies require that one person be in these vehicles at all times and this passenger would be
exposed to dangerous temperatures.
Vehicles that are transporting livestock that need to be temperature controlled are exempt from
the 3 minute idling requirement.
Vehicles that serve as portable service operations, where customers enter the vehicles to receive
services or make purchases, are exempt from the 3 minute idling requirement only if the engine
must be on to provide electricity, air conditioning or heat to the service portion of the vehicle.
This would include vehicles like libraries on wheels, bloodmobiles and Snap-On Tools trucks.
6. Are there medical exemptions to allow idling?
Yes. If, for example, a truck driver needs to use a CPAP machine while sleeping to treat sleep
apnea and has no alternate source of power other than the vehicle’s main engine, idling is
allowed while the driver is sleeping in a sleeper cab.
Vehicles that transport medically needy passengers and have no alternate power source are
allowed to idle to meet the temperature requirements of the patients on-board, and to power
necessary medical equipment. Drivers should keep documentation of the patient’s temperature
needs to show enforcement officers.
7. Does idling my asphalt truck to warm the asphalt qualify for the exemption at 14.3(b)2?
The exemption located at N.J.A.C. 7:27-14.3(b)2 is applicable only to those vehicles whose
primary diesel engine is used for operations, other than propulsion, passenger compartment
heating and passenger compartment air conditioning, that are specifically designed by the truck
manufacturer. Asphalt trucks are designed to have a separate power source that provides the heat
necessary to treat the asphalt, so asphalt trucks that use exhaust gas to "warm" the asphalt in the
bed of the truck do not qualify for this exemption.
8. Am I allowed to idle while my diesel vehicle is being repaired?
Yes, as long as someone is actively working on the vehicle and the vehicle needs to be running
to ensure effective diagnosis and repair.
9. If my vehicle is waiting to be inspected, am I allowed to idle?
Yes, vehicles can idle while being inspected or waiting to be inspected by a State or Federal
motor vehicle inspector when the vehicle needs to be running to ensure effective diagnosis and
repair. However, if you are waiting in line, shutting off the engine will save fuel and money as
well as benefit the environment.
10. Can I idle my vehicle to regenerate my diesel particulate filter (DPF)?
Most diesel particulate filters “regenerate” or clean themselves during normal operation of the
vehicle. For these vehicles, driving on the normal driving cycle will keep the filter clean and
operating correctly. For a few vehicles that are model year 2007 or later, the regeneration cycle
can only occur while the vehicle is parked and idling. In these circumstances only, the
exemption at N.J.A.C. 7:27-14.3(b)5 applies while the DPF is regenerating. For these vehicles,
there is an indicator light in the cab that shows that regeneration is occurring. Enforcement
inspectors and police officers will need to see this light in order to ensure that idling is happening
for DPF regeneration purposes only.
11. Are Alternate Power Units (APUs) subject to idling regulations?
APUs are devices attached to diesel vehicles that can power the vehicle’s heating and air
conditioning systems without the need to have the engine turned on. These devices allow truck
drivers to sleep comfortably without the noise, smell and health effects of diesel exhaust. In
addition, APUs are cost-effective and often pay for themselves within a year or two of
installation due to reduced fuel costs and less frequent maintenance. At the current time, APUs
are not subject to idling restrictions. Information on APUs is available from USEPA at http://www.epa.gov/smartway/technology/idling.htm .
12. What if my vehicle is stuck in traffic for more than 3 minutes?
Motor vehicles stopped in traffic are exempt from the 3 minute idling limit. However, if the
traffic is not moving, shutting off the engine will save fuel and money as well as benefit the
13. Are emergency vehicles allowed to idle?
By their nature, emergency vehicles such as fire, police, ambulances or public utility trucks may
need to keep engines running to operate emergency equipment when they are engaged in the
process of performing emergency services. They are exempt from idling restrictions, but only
when actively being used for emergency services. Police vehicles are exempt if idling is
necessary to power on-board computers.
14. Are regular gasoline-powered vehicles subject to idling restrictions?
Yes, gasoline-powered motor vehicles are subject to similar idling restrictions including a 3
minute limit on idling (see N.J.A.C. 7:27-15). However, diesel vehicles emit much more fine
particulate matter, commonly called soot, than do gasoline-powered vehicles and they will
continue to be the subject of increased enforcement oversight.
15. Are off-road construction vehicles subject to the 3 minute idling limit?
Yes, subject to the existing exemptions.
16. Will DEP still enforce the 3 minute idling limit now that the sweep is over?
These regulations have been in place since the mid-1980s and we will continue to enforce them
as part of the Department's renewed emphasis on reducing fine particulate matter from diesel
vehicles. Reducing idling also conserves fuel and reduces greenhouse gases.
17. Who can enforce the regulations besides DEP?
Nearly all county health departments have been delegated authority to enforce the Department's
air regulations, which include the idling standards. In addition, State and local police
departments can enforce the standard on public roadways and on private property. Additional
information on how to cite violations is available at http://www.stopthesoot.org/sts-idle-enforce.htm .
18. Am I exempt from New Jersey’s idling requirements if my vehicle has been designated
by CARB as a “Certified Clean Idle” vehicle?
The “Certified Clean Idle” designation and accompanying sticker apply to diesel vehicles of
model year 2008 or newer, which are sold with diesel particulate filters. In California, no idling
beyond 5 minutes is allowed, including idling for sleeper berth use, so vehicles with the
“Certified Clean Idle” sticker are allowed to idle while the driver is using the sleeper berth only.
In New Jersey, only those vehicles with sleeper berths that have a model year 2007 or newer
engine, or have been retrofitted with a diesel particulate filter, will be allowed to idle past the
three-minute limit, but only while the driver is resting or sleeping in the sleeper berth. Idling is
allowed if the vehicle qualifies for one of the listed exemptions specifically detailed in the idling
regulation, N.J.A.C. 7:27-14.3(b)7 (http://www.state.nj.us/dep/aqm/Sub14_Rule.pdf).
19. Will reducing idling really make a significant difference in reducing soot?
According to the USEPA, the U.S. Department of Energy, and other organizations, the average
long-haul truck idles at least 1,830 hours per year, and, in the process, uses $4,400 of
unnecessary fuel and emits 17 tons of carbon dioxide, 10 pounds of fine particles and 615
pounds of nitrogen oxides every year. Reducing idling will lower maintenance costs on each
vehicle, save fuel and protect public health and air quality.
20. Wouldn't the continual shutting off and turning on of diesel engines actually damage
the engine and emit more soot than idling?
Idling an engine for more than about 10 seconds actually uses more fuel than if the engine had
been turned off. It is more efficient to turn an engine off if it will be stopped for more than 10
seconds. Frequent restarts of an engine will not have a negative impact on engine components.
21. Isn't it bad to drive a cold engine if it hasn't been warmed up?
Electronically controlled engines need no more than about 30 seconds to warm up. Driving a
vehicle cuts warm-up times in half. The best way to warm up an engine is by driving it, while
avoiding rapid acceleration and high speeds for approximately the first four miles in cold
22. Whom should I contact with questions or complaints?
DEP 24-hour Hotline – for reporting suspected violations (877) WARN DEP (877 927-
DEP Diesel Risk Reduction Program (609) 292-7953 -- for general questions
Northern Field Office (973) 656-4444
for complaints in Bergen, Essex, Hudson, Hunterdon, Morris, Passaic, Somerset, Sussex, Union
and Warren counties
Central Field Office (609) 292-3187
for complaints in Burlington, Mercer, Middlesex, Monmouth, and Ocean counties
Southern Field Office (856) 614-3601
for complaints in Atlantic, Camden, Cape May, Cumberland, Gloucester and Salem counties