NEW JERSEY DEPARTMENT OF TRANSPORTATION

SPEED LIMIT ENFORCEMENT

RACM Analysis

Michael Baker Jr., Inc. Speed Limit - 1

Control Measure:

Enforce posted speed limits on freeways.

Description:

By traveling in excess of the posted speed limit, vehicles on the road emit 

pollutants as a far different rate then they would should they travel at the limit. 

This analysis estimates the impact of lowering average travel speed on all 

freeways in the state through an expanded enforcement presence in the form of 

increased police patrols.

Vehicles emit higher emissions at speeds greater than 65mph. NOx emissions 

are significantly lower at 55mph compared to 65mph. Hence, by enforcing speed 

limits to 55mph NOx emissions can be reduced. The downside to this is that the 

VOC emissions are higher at 55mph than at 65mph. Enforcement of the 65 MPH 

speed limit will have less of an effect as average speeds are only slightly higher. 

Since PM2.5 and SO2 emissions are not impacted by speed changes, this 

project would have no impact on those pollutants.

Methodology:

Total Vehicle Miles of Travel (VMT) were available for every county, and the New 

Jersey Congestion Management System (NJCMS) was used to estimate the 

percentage of total travel in each county on 55 MPH and 65MPH freeways. The 

estimated percentages are shown in Table 1

The basic assumption is that the average travel speed on all freeways in NJ is 67 

MPH, a values obtained from the “18 Month Study Report on 65 MPH Speed 

Limit in New Jersey” found on the NJDOT website. It is assumed that the

enforcement program would reduce average speeds to the posted limit. 

Emission rates were calculated for a composite vehicle traveling at 65mph and at 

55mph using MOBILE6.2 and setups for each of the New Jersey counties for 

each season (summer and winter.) Since MOBILE 6.2 does not calculate 

specific emission rates for speeds in excess of 65MPH, a straight line projection 

using the 55MPH and 65MPH emission rates was used to obtain the 67MPH 

rates. The difference between the emission rates was used along with the total 

freeway VMT to calculate emissions benefits. Summaries of these calculations 

are found at the end of this project description.

Inputs/Assumptions:

 The average travel speed on New Jersey freeways is 67 MPH

 This enforcement program would reduce average speeds to the posted limit

 Estimates of total VMT were readily available, the NJCCMS was used to 

estimate the percentage of travel on 55 MPH and 65 MPH freeways in each 

county.
NEW JERSEY DEPARTMENT OF TRANSPORTATION

SPEED LIMIT ENFORCEMENT

RACM Analysis

Michael Baker Jr., Inc. Speed Limit - 2

County

Percent of Total 

VMT On Freeways 

(From the NJCMS)

Estimated % 

on 55 MPH 

Freeways

Estimated % 

on 65 MPH 

Freeways

Atlantic 42.2% 11.07% 31.18%

Bergen 44.5% 11.67% 32.87%

Burlington 51.1% 13.39% 37.73%

Camden 41.6% 10.89% 30.68%

Cape May 41.2% 10.79% 30.40%

Cumberland 33.1% 8.67% 24.41%

Essex 56.4% 14.79% 41.65%

Gloucester 53.2% 13.94% 39.27%

Hudson 51.0% 13.36% 37.62%

Hunterdon 46.8% 12.26% 34.52%

Mercer 45.3% 11.87% 33.44%

Middlesex 35.2% 9.23% 26.00%

Monmouth 42.2% 11.05% 31.12%

Morris 59.2% 15.51% 43.69%

Ocean 47.3% 12.39% 34.90%

Passaic 33.7% 8.83% 24.86%

Salem 56.0% 14.67% 41.32%

Somerset 50.2% 13.16% 37.07%

Sussex 2.7% 0.00% 2.70%

Union 68.0% 17.81% 50.18%

Warren 59.5% 15.58% 43.90%

Table 1: Estimated Percentage of Total VMT on Freeways from NJCMS

Results:

Emission Reductions (Statewide):

Pollutant

Type

Analysis Year 2010

Tons/Day Tons/Year

VOC -0.35 -

NOx 4.88 1,845.58

PM2.5 - 0.00

SO2 - 0.00

*Note: Negative means increase in emissions
NEW JERSEY DEPARTMENT OF TRANSPORTATION

SPEED LIMIT ENFORCEMENT

RACM Analysis

Michael Baker Jr., Inc. Speed Limit - 3

Ozone Analysis – Daily Benefits in New Jersey

Benefits (Reductions)

Ozone Non-Attainment Area

New York-N. New 

Jersey-Long Island,

NY-NJ-CT

Philadelphia-WilmingtonAtlantic City

PA-NJ-MD-DE

VOC (Tons/Day) -0.23 -0.13

NOx (Tons/Day) 3.16 1.71

*Note: Negative means increase in emissions

PM2.5 Analysis – Annual Benefits in New Jersey

Benefits (Reductions)

PM2.5 Non-Attainment Area

New York-N. New JerseyLong Island, NY-NJ-CTPhiladelphia-Wilmington

PA-NJ-DE

NOx (Tons/Year) 1,206.63 295.66

PM2.5 (Tons/Year) 0.00 0.00

SO2 (Tons/Year) 0.00 0.00

*Note: Negative means increase in emissions

COST/BENEFIT ANALYSIS

Assume approximately 5 officers are needed to patrol 20 miles of freeway 24 hrs 

a day. 

Capital Cost = $33,000/officer over 7 years (vehicle, equipment, etc)

Annual Maintenance Cost = $10,000/officer (maintenance cost)

Annual Operating Cost = $52,000/officer (Salary, overhead)

Annualized Cost = $66,714/officer/year

Annual Cost/Mile of Freeway = $16, 678.50

Total Statewide Cost = 757.1 Miles x 16,678.50 = $12,627,292/Year

Total cost for the various non-attainment areas are as follows:
NEW JERSEY DEPARTMENT OF TRANSPORTATION

SPEED LIMIT ENFORCEMENT

RACM Analysis

Michael Baker Jr., Inc. Speed Limit - 4

County

Miles of 

Freeway

Patrol 

Officers 

Required

Estimated Cost For Each Non-Attainment Area

Ozone PM 2.5

NY-NJCTPA-NJDE-MDNY-NJCTPA-NJDE

Atlantic 48.7 12 - $812,476 - -

Bergen 54.9 14 $915,804 - $915,804 -

Burlington 55.5 14 - $926,088 - $926,088 

Camden 38.7 10 - $645,514 - $645,514 

Cape May 26.7 7 - $445,127 - -

Cumberland 17.7 5 - $294,394 - -

Essex 33.7 9 $562,113 - $562,113 -

Gloucester 51.8 13 - $863,417 - $863,417 

Hudson 29.3 7 $489,318 - $489,318 -

Hunterdon 19.0 5 $316,088 - - -

Mercer 38.6 10 - $643,586 $643,586 -

Middlesex 57.2 14 $953,246 - $953,246 -

Monmouth 40.9 10 $682,635 - $682,635 -

Morris 57.9 15 $965,619 - $965,619 -

Ocean 45.6 12 - $760,250 - -

Passaic 15.1 4 $251,488 - $251,488 -

Salem 21.2 5 - $353,691 - -

Somerset 34.7 9 $578,022 - $578,022 -

Sussex 0.8 0 $13,177 - - -

Union 40.9 10 $682,313 - $682,313 -

Warren 28.4 7 $472,927 - - -

Total 757.1 192.0 $6,882,749 $5,744,543 $6,724,143 $2,435,019

Cost/Benefit Results

Pollutant

Cost/Benefit for Each Pollutant

Ozone PM 2.5

NY-NJ-CT PA-NJ-DE-MD NY-NJ-CT PA-NJ-DE

VOC ($/Ton/Day) Increase in VOC Increase in VOC - -

NOx ($/Ton/Day) $101,338 $140,451 - -

NOx ($/Ton/Year) - - $55,290 $67,693 

PM2.5 ($/Ton/Year) - - No Change No Change

SO2 ($/Ton/Year) - - No Change No Change

* Daily Costs used in calculation of cost/benefit ratio are Annual costs divided by 250