An analysis of the I-90 ramp closure system in Minnesota found benefit-cost ratios ranging from 0.13:1 to 3:1 with varying estimates of crash and delay reductions.

October 1999
Interstate 90,Minnesota,United States

Summary Information

This report evaluates the Minnesota Department of Transportation (Mn/DOT) operational procedure for restricting highway access when driving conditions are unsafe. During severe snowstorms and major incidents, mainline gates divert traffic from highways and gates located on entrance ramps prohibit highway access. Generally, Mn/DOT personnel report to gate locations and activate warning signs with amber lights. Gate arms are then swung or lowered into place and gate arm lights are illuminated. Once gate arms are deployed, law enforcement personnel man gate locations for one to two hours.

In Fall 1998 and between March and August 1999, Mn/DOT's Office of Advanced Transportation Systems conducted analyses to document past procedures and to identify current operational issues associated with gate systems. A benefit-to-cost analysis compared potential savings to estimated costs, and a winter storm case study compared costs for clearing a gated highway section to costs for clearing a section without gates.


The benefit-to-cost analysis focused on costs of the Interstate 90 gate system and associated benefits due to delay and accident reductions. The annual frequency of snow/ice related accidents and hourly volume data were used in the analysis. Total system costs were calculated assuming deployment costs of 159,700 dollars plus five percent operations and maintenance costs over 10 years. The potential range of benefits and benefit-to-cost ratios are shown in Table 1.

Table 1: Range of Interstate 90 Gate System Benefits/Costs

Potential Range of Benefits over 10 Years
Benefit-to-Cost Ratio
10% Reduction in Delay (Low Volume) + 0% Accident Reduction = $28,096
20% Reduction in Delay (High Volume) + 1% Accident Reduction = $168,981
20% Reduction in Delay (High Volume) + 2% Accident Reduction = $217,636
30% Reduction in Delay (Low Volume) + 3% Accident Reduction = $230,253
40% Reduction in Delay (High Volume) + 0% Accident Reduction = $240,651
40% Reduction in Delay (Low Volume) + 3% Accident Reduction = $258,350
20% Reduction in Delay (High Volume) + 3% Accident Reduction = $266,290
50% Reduction in Delay (Low Volume) + 4% Accident Reduction = $335,101
40% Reduction in Delay (High Volume) + 4% Accident Reduction = $435,270
70% Reduction in Delay (High Volume) + 5% Accident Reduction = $664,414

Benefit Comments

No comments posted to date

Comment on this Benefit

To comment on this summary, fill in the information below and click on submit. An asterisk (*) indicates a required field. Your name and email address, if provided, will not be posted, but are to contact you, if needed to clarify your comments.


Documentation and Assessment of Mn/DOT Gate Operations

Author: BRW, Inc.

Published By: Minnesota DOT

Prepared by BRW, Inc. for the Minnesota DOT

Source Date: October 1999



Average User Rating

0 ( ratings)

Rate this Benefit

(click stars to rate)

Goal Areas


Typical Deployment Locations

Rural Areas


automated gate closure

Benefit ID: 2007-00473