SmartWay*
MENTAL PROTECTION AGENCY »
U.S. ENVIRONMENTAL PROTECTION AGENCY
Reducing Highway Speed
A Glance at Clean Freight Strategies
ENERGY &
FUEL SAVINGS
Gallons Saved:
1,292 gallons
CO2 Savings:
13 metric tons
Fuel Economy
Increase:
9%
MPG
(original 6 mpg):
7.12 mpg
Reduction in Fuel
Consumption:
9%
Fuel Cost Savings:
$4,912
Reducing hiqhu/ay speed by 5 miles per hour can cut fuel use and greenhouse gas
emissions by about 7 percent while extending the life of a truck's engine, tires
and brakes. An example is a long-haul truck that reduces its top speed from 65 to
6O miles per hour saves over 1,200 gallons of fuel, cutting its annual fuel bill by
$4,9OO while eliminating nearly 13 metric tons of greenhouse gas reductions.
What is the challenge?
A typical combination truck spends 65 percent or more of its operating time at highway speeds.
Line-haul trucks spend even more time on highways. The impact of speed on fuel economy
depends upon many factors including vehicle aerodynamics, engine speed and operating
conditions. As a general rule of thumb, increasing speed by one mile per hour reduces fuel
economy by about 0.1 miles per gallon. Excessive speed also leads to higher maintenance costs
of by increasing wear on the engine, tires and brakes.
What is the solution?
Speed management is an easy and effective way to save fuel, reduce emissions, and prevent
excess wear. A trucking firm or driver can adopt a speed policy at little or no cost. The most
successful speed management policies combine technology (e.g., speed settings on electronic
engine controls) with driver training and incentive programs to encourage drivers to maintain
speed limits. Most new truck engines are electronically controlled so the cost of changing
maximum speed settings on these engines is negligible.
Savings and benefits
Although fuel savings may vary by vehicle and speed range, a combination truck driving 55
miles per hour uses up to 7 percent less fuel than a similar truck driving 65 miles per hour. Other
analyses indicate that reducing the maximum speed of a typical long-haul truck from 65 miles
per hour to 60 miles per hour could save about $4,900 in annual fuel costs.
Reducing speed can cut truck maintenance costs and reduce the frequency of maintenance
work. The time between engine overhauls, for example, is directly related to fuel use. Holding
maximum speeds at 60 rather than 70 miles per hour reduces engine wear and extends time
between engine rebuilds, saving hundreds of dollars per truck each year while keeping revenue-
earning equipment on the road. Fleets that adopt speed policies report additional savings
due to fewer brake jobs and other service work.
Reducing highway speed does increase travel time. Assuming ideal conditions, a
trucker driving 60 miles per hour instead of 65 miles per hour could spend about
eight percent longer on the road. Of course, the time difference may be less,
depending upon road conditions, weather, and traffic congestion and road
construction. If a trucking company pays its drivers by the mile or by the load
rather than by the hour, reducing speed should not increase labor costs. It
could reduce the productivity of trucking operations since slower trucks may
carry fewer loads. However, the benefits of lower fuel and maintenance
costs combined with less frequent out-of-service work and driver safety
considerations may well outweigh any costs associated with an increase in
delivery time.
Continued
U.S. EPA SmartWay | EPA-420-F-16-029 | June 2016 | Jwww.epa.gov/smartway
-------
SmartWay
MENTAL PROTECTION AGENCY »
U.S. ENVIRONMENTAL PROTECTION AGENCY
Reducing Highway Speed
A Glance at Clean Freight Strategies
Continued
NEXT STEPS
1A trucking com-
pany interested
in saving fuel and
lowering the cost
and frequency of its
equipment mainte-
nance should con-
sider adopting a
speed management
policy, particularly
if its trucks spend
considerable time on
highways.
2A number of well-
managed truck
fleets have programs
in place to reduce
highway speed and
promote safe driv-
ing by using driver
training, incentive
programs, and elec-
tronic engine con-
trols. A trucking fleet
interested in follow-
ing these examples
may learn more by
reading articles and
fleet profiles in truck
industry publications.
3When purchas-
ing new vehicles,
a trucking company
may also consider
specifying equipment
designed to optimize
truck performance
at lower maximum
speeds. Trucking
companies and driv-
ers interested in
learning more about
the effects of speed
on fuel economy may
contact truck and
equipment manufac-
turers or their state
and national trucking
associations
------- |