The primary reason that SR 167 corridor cities have seen a rise in population is due to the relative affordability of housing in the corridor. The median home price in the Green River Valley is 20 to 34 percent lower than in the greater Seattle- Bellevue area.
Sound Transit, King County Metro, and Pierce Transit provide transit service on SR 167.
When possible, freight haulers avoid peak travel periods by scheduling their travel during off-peak times, but many must drive during the peak period to meet customers’ needs.
New lanes and longer ramps will reduce weaving as vehicles enter/exit.
A Mix of Solutions is Needed
The study found that growth in future population, employment and freight movement on SR 167 would overwhelm any added lanes that could reasonably be assumed to be built by 2030. Therefore, WSDOT recommends that a mix of solutions is needed to address growing transportation demand.
Highway and street improvements will need to be accompanied by increases in local and express transit service, commute trip reduction programs and operating new lanes as high-occupancy toll (HOT) lanes
Ways to Manage Growing Demand
Currently, travel by different modes on SR 167 is as follows: 59 percent drive alone; 33 percent carpool; 4 percent use Sound Transit rail; and 4 percent use buses (southbound p.m. peak hour).
Over 4,000 people use local transit routes in the study area, with 800 people using express buses (to Bellevue/Overlake). Currently there is no express bus service to downtown Seattle, but Sounder Rail carries 3,600 commuters each day to/from downtown Seattle.
A comparison of current travel times showed that traveling by rail was faster than traveling by car from all Sounder Rail stations in the Valley except Tukwila where the times were equal.
WSDOT and the Corridor Working Group recommend that the jurisdictions adopt policies and implement actions that support transit investments. (An analysis of the cost to increase transit service was not included in this study.)
Keeping Freight Moving
Trucks carrying goods to our local stores and also to/from the Ports of Tacoma and Seattle play a vital role in our region’s economy. One-third of the region’s warehouses are located in the Green River Valley, and it is the third largest distribution center on the West Coast.
An estimated 33 percent of all regional truck trips generated by the Ports of Seattle and Tacoma are destined to locations in the Green River Valley.
More than 12,000 trucks use SR 167 every week day with freight representing 10 percent of total traffic volume. By the year 2030 there will likely be twice as many trucks on the highway.
The recommendations include special considerations for trucks including reducing roadway curves and lengthening on-ramps at key locations to provide additional time and space for large trucks to gain speed and merge into traffic more easily and safely.
Safety
Over a three-year period from 2002 to 2005, 1,600 collisions occurred on the SR 167 mainline and ramps. The study identified 10 high accident locations in the corridor.
Most of the collisions are related to high congestion levels and occurred during the peak traffic periods in the morning and afternoon. Collisions involving trucks were similar in rate of occurrence and severity as total traffic.
The computer traffic forecasting model predicted a decrease in collisions with additional lanes. The auxiliary lanes will add lanes to those areas where merging conflicts occur, thereby reducing collisions and streamlining traffic flow.
Improving ramps will enhance safety and truck mobility by providing more room for vehicles to gain speed or slow down when entering and exiting SR 167.