METHODOLOGY:

The study methodology consisted of the following:

• The regional travel demand model maintained by the Metropolitan Council was used to forecast the results on traffic operations and mode split of opening the HOV lanes to all traffic.
• Market research was conducted to assess the viewpoints of travelers who use and do not use the HOV lanes, as well as the general population of commuters.
• Mn/DOT's second quarter 2001 HOV Report data was used to validate the travel demand model in the study corridors.
• Field data was collected on violation rates in the HOV lanes.
• The U.S. DOT's Intelligent Transportation System (ITS) Deployment Analysis System (IDAS) model was used to quantify the benefits and disbenefits of opening the HOV lanes to all traffic based on the output of the regional model; the benefits were then compared to the costs of opening the lanes.

RESULTS:

The study found an estimated $10 million in 2001 dollars in potential benefits if the lanes were opened to all traffic. This benefit was generated almost entirely by regional travel time savings, but also included reliability, emissions and fuel consumption improvements. Even though vehicle miles of travel (VMT) would increase due to the shift of carpoolers and bus riders to single-occupant vehicles (SOV), vehicle hours of travel would decrease due to improved traffic flow.

The one-time capital costs of opening the lanes was estimated to be $20 million or $41 million, depending on whether it would be necessary to 'buy back' the I-35W lane from the federal government. The largest single cost (aside from the buy back) was estimated to be $9 million for environmental studies on both I-394 and I-35W. Additional costs could result from litigation arising from changing the original EIS assumptions regarding lane operation, but they were not included in the analysis. Major operating costs were split between foregone federal revenue related to bus operation in dedicated transit facilities, and the costs associated with the operation of additional buses.

The study estimated that in 2020, the monetary value of opening the expanded HOV system to all traffic would be approximately $13 million. Operating costs would increase due to an increase in the number of buses required in 2020 to maintain headways. The 2020 model forecast worsening congestion, with or without the HOV lanes.

Estimation of Benefits - The regional travel demand model was used to estimate the travel time and speed, throughput and mode shift changes. The outputs of the model were input directly into the IDAS software program. IDAS was used to estimate the safety, emissions, fuel consumption, and travel time reliability impacts.

The performance measure estimates included:

• Average speeds and travel times;
• Travel time reliability (hours of delay saved);
• Crashes by type (fatality, injury, and property damage only);
• Air quality/emissions (hydrocarbons, carbon monoxide, and oxides of nitrogen), and
• Fuel consumption

These impacts were estimated for the HOV facilities and their adjacent general-purpose lanes, as well as systemwide. The resulting changes were summed across the morning and afternoon peak periods for each year. Established per unit dollar values were then applied to the sum of the changes as follows:
 

The dollar values for each impact category were then summed to estimate the average daily impact value from opening the HOV lanes to all traffic. This figure was multiplied by 247, the number of days per year the HOV lanes were operated, to provide the annual benefit/impact estimate.

Estimation of Costs - The study assumed that only nominal improvements to the facilities themselves would be made if the lanes were opened to all traffic. Other cost items include additional buses necessary to maintain existing headways due to the travel time increases in the corridors, drivers and operating and maintenance costs for these new buses, annual federal revenue loss to transit providers from operating service in HOV corridors, federal pay-back for the I-35W HOV lane funding, and replacement cost for the I-394 and I-35W environmental impact studies (EISs). Possible litigation costs resulting from these revised EISs were not included.

CONCLUSION:

Although opening the HOV lanes to all traffic is currently a net benefit, the study authors recommend against it based on the following:

• Significant institutional issues involving buy backs from the federal government, revised EISs, and potential litigation whose cost was not included in the analysis.
• Policy implications of moving the region toward reliance on future highway construction and expansion and away from development of alternative transportation systems and choices.
• The difficulty of reclaiming the lanes for HOV if conditions change. The strategy of discouraging SOV use will have been abandoned before it was permitted the opportunity to mature into an effective system.

The authors conclude by recommending that Mn/DOT explicitly consider the HOT lane approach in its future highway planning activities. The potential benefits include:

• Increased usage of HOV lane.
• Reduced congestion in non-HOV lanes.
• Overall optimization of facility usage.
• Peak demand spread over longer period.
• Additional revenue to pay for transportation improvements.
• Customers make their own decisions regarding the trade-off between money and time.