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HOV Studies and Surveys

Pilot and Demonstration Projects | Studies | Surveys

Pilot and Demonstration Projects

SR 167 HOT Lanes Pilot Project

One way of maximizing HOV lane efficiency is conversion of HOV lanes to high occupancy toll (HOT) lanes. We are evaluating the feasibility and benefits of building or converting one or more HOV lanes to HOT lanes through a pilot project on SR 167 between Renton and Auburn.

HOT lanes on SR 167 allow solo drivers to use the HOV lanes for a toll when there is room. This pilot project is the first HOT lane in the state and will provide data for HOT lane or express toll lanes in other locations. The four-year pilot project opened on May 3, 2008.

An evaluation of the first year of HOT lane operations on SR 167 showed that HOVs were able to maintain pre-conversion speeds while providing travel time savings and higher vehicle throughput for other freeway users.

Hours of Operation Demonstration Project

In 2003 we opened HOV lanes to all drivers between the hours of 7 pm and 5 am on freeways east of I-405. The results of this change were monitored through 2005. In June 2006 we issued a final report outlining the results. The major operational changes have been a slight decrease in congestion and a minor increase in average speeds around 7 pm.

These new hours of operation have been successful and are expected to continue as long as operations remain positive.

Vancouver HOV Lanes Pilot Project

An HOV lane pilot project operated on southbound I-5 from 2001 - 2005 during the morning commute in Vancouver, WA. By the end of the project, this HOV lane carried more people per lane than either of the adjacent freeway lanes. The number of bus riders and carpools increased, HOV speeds and reliability improved, and the public generally approved of the lanes.

Although the project met most of its performance goals, other circumstances resulted in a recommendation by the Southwest Washington Regional Transportation Council to end the pilot. These circumstances included insufficient park-and-ride facilities, cutbacks on transit service coupled with an increase in fares, and a lack of connecting HOV lanes into Portland.

Travel time through the corridor has not improved since the HOV lanes were opened to general traffic.


Puget Sound HOV Pre-Design Studies, Final Report, 1997

The Pre-Design Studies were undertaken to look at long-range planning for, and potential improvements to, the HOV system.  The studies took place between 1994 and 1997. They were broken into two phases and produced a number of products. Together they form the central planning documents guiding HOV programming and construction over the past decade. 

A primary focus of the studies was to improve access into and out of the lanes, and to provide connections between HOV lanes on intersecting freeways.  The studies also include a series of conceptual designs and prioritized treatments to improve operation, performance, safety, and reliability of the HOV system.

The Final Report provides a summary of the findings and conclusions of the various Pre-Design studies.  The Puget Sound HOV Pre-Design Studies Final Report is available as 15 pdf's:  

Puget Sound Park & Ride System Update, Final Report, 2001

This four-county, 30-year, park-and-ride (P&R) system plan provided the first comprehensive look at P&Rs since the 1970's.  It identified regional long-range P&R needs in King, Kitsap, Pierce, and Snohomish Counties.

The plan provided corridor-level demand estimates for three planning horizons: short-term (2000-2006), mid-range (2007-2015), and long-range (2016-2030).  Recommendations consist of generalized locations and cost estimates for P&R lots by major commute and transit corridors in each county.  The plan also included a new demand estimation technique, preliminary cost estimates, and intelligent transportation system (ITS) integration suggestions.

The Puget Sound Park & Ride System Update is available as 12 pdf's: 


HOV User Survey

An HOV User Survey (pdf 1.5 mb) was published in December 2007. This survey provided some interesting results about who is using the HOV lanes, why, and how users might travel without HOV lanes in Washington State. Some of the findings include:

  • HOV lanes do provide an incentive to carpool or take the bus.
  • Freeway HOV lane closure would impact both freeways and side streets, and lengthen peak commuting hours.
  • Saving money, convenience, and stress reduction are of equal or more importance than time savings for many users.
  • Most carpools are composed of household members, and these "family-pools" behave very similarly to standard carpools.  Both types of carpools would be expected to switch to single-occupant driving at about the same rate without HOV lanes.
  • Ride-sharing is a choice for most users.  A large portion of regular HOV users regularly drive alone during the peak commuting hours.
  • Employer incentives play a large role in the decision to take shared rides.
  • 70% of mid-day carpooling is for work, appointments/meetings, or shopping.

Read a more detailed summary of the report, or download the final report (pdf 1.5 mb) here.

Public Opinion Survey

We regularly ask drivers for their opinion about the HOV system. A 2007 HOV opinion survey (pdf 84 kb) performed by the Transportation Center at the University of Washington showed that HOV lanes in the Puget Sound region are popular with both HOV and solo drivers. The poll showed that 76% of solo freeway drivers who did not usually use the HOV lanes still thought the lanes were a good idea. Of this same non-user group, 66% felt that HOV lane construction should continue, and 62% disagreed with the idea of opening the HOV lanes to all traffic all the time.

Updated March 2010.