Dynamic priced toll lanes to open this weekend on WA167 - third in US

5am Saturday morning (2008-05-03 05:00) Washington state DOT and their hired help from Jacobs, IBI and ETC are due to fire up America's and the world's third dynamically priced toll lanes on Washington State Route 167 (WA167), a commuter expressway on the southeast side of the Seattle metro area. Electronic Transactions Consultants (ETC) have written algorithms for the pricing that take into account conditions on the untolled general purpose lanes as well as in the tolled lanes.

In general the denser the traffic sensed the higher the price goes in order to discourage congestion causing volumes of traffic in the tolled lanes. Very high density and little movement in the untolled lanes is used to assess willingness top pay for the time savings in the toll-managed lanes.

The WA167 ETC software gives the toll lane managers the ability to price simple and crude with large infrequent price changes all over, or to go increasingly discriminating pricing with more frequent smaller price changes and differential prices in ten separate toll zones. The ETC user interface displays conditions real time in the different highway segments from in-pavement loops, so managers can adjust its operation with a keystroke or two.

This is a 3+3 lane expressway between Renton and Auburn with a concurrent priced lane on the left of a pair of general purpose lanes in each direction. The segments between interchanges have designated access/egress crossover zones and white double-striped lane marking prohibiting crossovers outside those zones.

Called HOT lanes (High Occupancy free, others Tolled) they operate 5am to 7pm (05:00-19:00) seven days a week both directions, the same way old HOV lanes in the region work.

The WA167 project is a $18m four year pilot program funded with a mix federal value pricing grants and state funds. It involves HOV to HOT lanes conversion - minor pavement work, movement of barrier to provide enforcement zones, striping, and the toll system.

Northbound, the morning peak hour direction is 21km (13 miles) with six different toll zones defined by access/egress points between interchanges.

In the southbound direction the facility is 14.5km (9 miles) long with four toll zones.

Tolls will vary from a minimum 25c to $9.00. After $9.00 tolls are hit and there is a need to restrict traffic further, all SOVs (single occupant vehicles) will be barred and access will go HOV-Only. Dynamic message signs just ahead of the access crossovers will be displaying the current toll rate or bar on tollpayers.

Tolls are levied by entry zone and are therefore levied at a flat rate regardless of the number of segments traveled before exiting the facility.

The WA167 HOT lanes project is mainly a traffic management exercise to make use of spare capacity in the HOV lanes by allowing SDOV buy-in while the dynamic pricing manages them for free flow movement. It is not principally a revenue raiser but the hope is from about the third year onward the toll revenues will be covering the $2.24m of annual operations costs - which includes not only normal maintenance and toll collection costs but also stepped up incident response patrols and policing costs.

Patty Rubstello the tolling and systems development manager for the project says they wanted an ability to input general purpose lane conditions data into the pricing because that varies enormously with chokepoints at each end.

In the mornings the chokepoint is at the I-405/WA167 interchange with multiple lane drops to a primitive 3 loop cloverleaf interchange. There is a project to rebuild this as part of I-408 widening with a high level HOT lane to HOT lanes direct connector bridge (see nearby) but this is an expensive project several years off. At the southern end of the WA167 is a similar chokepoint in the evenings from backups from the merge with I-5.

Rubstello says that as an HOV facility WA167 has been running about 1,000 vehicles per hour in the peak hours on average so it has the capacity to sell an average of around 600 trips/hour to SOVs, given a 1600 vehicles/hour maximum to assure always 45+mph travel (72+km/hr).

She says that trips in the HOT lanes of 10 to 15 minutes will usually save more than 20 minutes in peak hours given general purpose lane (GPL) trips of up to 38 minutes.

TransCore gear

The tolling system uses TransCore gear and involves about 20 (plus spares) Encompass-6 readers and antennas and eGo Plus 900 MHz passive backscatter read-write sticker tags branded Good-To-Go. The financial accounts of WA167 tolling are being kept separate but Good-To-Go transponders are being supplied out of the one WSDOT owned customer service facility operated by TransCore at Gig Harbor for the dualled Tacoma Narrows bridge that has been tolling for over a year.

Switching between HOV and toll

A difference is that WA167 patrons can get a metallic shield that masks the eGo sticker tag for use when a toll account holder is entitled to a non-tolled ride because there are two or more occupants in the vehicle.

Encompass sixes

The TransCore Encompass-6 reader will handle simultaneously two of a possible six transponder protocols. WSDOT is operating the readers with the ASTMv6 Hughes protocols for the active Telematics transponders used widely for the CVISN weigh station bypass by trucks.

Rubstello says the thought was initially that the CVISN transponders might work well as a substitute for the sticker tag and the metallic signal masking shield. However she says that the Encompass-6 readers are not yet properly writing back to the CVISN transponders.

Write-back is being used for enforcement. An enforcement cop who pulls over a motorist has a handheld reader and will use that to read the history of the motorist's toll transactions as written back to the transponder. In tests the sticker tags are accepting write-backs nicely but the CVISN transponders aren't.

TransCore is promising WSDOT an eGo Plus mounting that involves a transparent sleeve attached permanently to the windshield and an insertable/removable sheet-tag for the SOV/HOV switchovers.

Ten toll points

Each of the ten tolling points in the WA167 HOT lanes have a pair of Encompass-6 antennas and readers, one for the tolled lanes and the other for the adjacent general purpose lane. The reader over the adjacent untolled lane is to help track and distinguish tollable from untollable vehicles with a higher degree of confidence than is possible with a single reader over the tolled lane, Rubstello says.

The antennas are mounted on slick one-piece median posts that curve over into cantilevered mast arms - a light installation possible because the system has no enforcement cameras which normally need the greater rigidity of a 2-posted solid gantry fully spanning a roadway.

On WA167 enforcement involves a cop watching for a light on the mast arm that flashes on for a toll transaction, and remains unlit on an untolled pass. The cop eyeballs the passing car and if only one occupant is seen, he radios upstream for a pullover of the suspect violator.

for more on WA167 HOT lanes

http://www.wsdot.wa.gov/Projects/SR167/HOTLanes/

Other dynamically priced roads

Other dynamically priced roads are:

- I-15 north of San Diego, a reversible 2-lane facility that is presently a simple single zone 'pipe', in one end and out the other, but is being extended into a more sophisticated multi-segment facility and widened to 3 or 4 lanes

- MN/I-394 west of Minneapolis which is a two-toll zone facility part two lanes reversible and partly a pair of single concurrent flow lanes

Wilbur Smith Associates were the prime consultant on the CA/I-15 lanes and prime contractor on MN/I-394, and wrote the specifications for both projects.

In the case of CA/I-15 TransCore was the systems integrator and wrote the dynamic pricing software.

In the case of MN/I-394 the systems integrators were Raytheon and VESystems. Raytheon wrote most of the code for the dynamic pricing, we're told. Cofiroute as the contract operator on MN/I-394 with experience on the 95 Express Lanesalso contributed to the software development. (CORRECTED/AMPLIFIED 2008-05-05 18:00)

TOLLROADSnews 2008-05-02