Assessment of Point Defiance Bypass for High-Speed Intercity Passenger Rail

Carter Danne, PE, PTOE

Abstract

This paper provides a synopsis of the assessment of high-speed intercity passenger rail improvements for the Point Defiance Bypass project and lessons learned from the assessment. Passenger rail has less of a carbon footprint than travel by airplane or standard automobile and in that aspect is a more sustainable mode of transportation.

As the lead federal agency, the Federal Railroad Administration granted funds to the Washington State Department of Transportation (WSDOT) to improve the Pacific Northwest Rail Corridor where Amtrak currently provides high-speed intercity passenger rail service. The existing service travels along Puget Sound around Point Defiance in Pierce County, where it encounters some operational limitations. In response to these limitations, WSDOT identified an alternate route to improve service that bypasses Point Defiance and travels inland on an existing rail alignment.

The author has summarized the highlights of the alternative’s effects on the transportation system. Of particular interest was how a relatively infrequent train crossing event, affected the system both for the short period of time during the crossing and after when queues clear as well as the overall peak hour. Effects on safety were also considered for the existing and alternative alignments; using collision prediction to illustrate the relative safety with the project.

Additionally, in preparing the project report and presenting the findings, several lessons were learned. The author has summarized these lessons to share the knowledge gained. In particular, specific lessons are included about the analysis and communication of complex project information.

INTRODUCTION

This paper provides a synopsis of the assessment of high-speed intercity passenger rail improvements for the Point Defiance Bypass project completed by Parametrix for the Washington State Department of Transportation (WSDOT). Additionally, lessons learned from preparing the assessment have been included in this paper. Passenger rail has less of a carbon footprint than travel by airplane or standard automobile and in that aspect is a more sustainable mode of transportation.

As the lead federal agency, the Federal Railroad Administration granted funds to the Washington State Department of Transportation (WSDOT) to improve the Pacific Northwest Rail Corridor where Amtrak currently provides high-speed intercity passenger rail service. The existing service travels along Puget Sound around Point Defiance in Pierce County, where it encounters some operational limitations. In response to these limitations, WSDOT identified an alternate route (hereafter referred to as the Bypass Route) to improve service that bypasses Point Defiance and travels inland on an existing rail alignment approximately 21 miles long. Exhibit 1 shows the alignment for the Bypass Route (the Build Alternative) as well as the Point Defiance Route (the Existing Alignment (No Action Alternative)).

Along the Bypass Route, the Point Defiance Bypass project will improve railroad tracks, crossings, and support facilities at various locations (including constructing a new second track adjacent to an existing main line between South Tacoma and Lakewood), and relocate the existing Tacoma Amtrak Station. Exhibit 2 shows the at-grade railroad crossings and station locations along the Bypass Route.

With the Bypass Route operational, Amtrak would shift its Cascades and Coast Starlight service to the Bypass Route and as a result fourteen more daily train trips would travel through the crossings shown on Exhibit 2 than would otherwise occur. The weekday AM and PM peak hours would contain one additional train trip.

STREET SYSTEM EFFECTS

A transportation discipline report was prepared in support of the Point Defiance Bypass Project Environmental Assessment. The effects on the street systems were summarized using a few different measures:

 Level of Service and Intersection Delay: These measures were primarily used to measure project effects against local agency standards for level of service conditions.

 Queuing: Maximum queues were used in an effort to more specifically illustrate the effects of train crossing events in the peak hours.

 Railroad Crossing Safety: The predicted accident recurrence intervals for the corridor were used to illustrate potential changes in traffic safety.

What follows are highlights from the transportation discipline report.

Level of Service and Intersection Delay

The year 2030 was used as the design year for comparing project effects on study intersections between the No Action Alternative and the proposed Project. Intersection level of service and delay in seconds per vehicle were studied at 47 public street intersections using Trafficware’s Synchro and PTV America’s VISSIM software. Exhibit 1 Proposed Project and No Action Alternative

Exhibit 2 At-Grade Crossings and Station Locations

The following factors figured prominently into the results documented in the transportation discipline report:

 Vehicular traffic volumes would remain similar between No Action and Build Alternatives.

 At one more train per hour, the train traffic increase above the No Action Alternative in the peak hours is small.

 With the Build Alternative, there will also be improvements to the railroad crossings and signal systems to accommodate the proposed changes.

Exhibit 3 below summarizes the conclusions from the intersection LOS and delay analysis.

Exhibit 3 Conclusions from LOS Analysis Quantity of Intersections Intersection Effect AM PM Peak Peak Hour Hour Slight to No Noticeable Effect 43 41 (Delay change of 5 seconds or less per vehicle) Improved Functioning 3 3 (Delay improvements of more than 5 seconds per vehicle) Adversely Affected 1 3 (Delay increases greater than five seconds per vehicle)

Of the intersections adversely affected, only one operates at a substandard LOS (below LOS D): Thorne Lane SW and Union Avenue SW, which operates at LOS F. However, by examining the system of intersections, the nearby two Thorne Lane SW Interstate 5 ramp intersections experience reduced delays, offsetting the increase in delay at this intersection. Given that the LOS and delay results are based on the traveler’s experience over an hour, maximum queues were also studied in an effort to the depict the specific effects of a train crossing event.

Queues

In 2030, vehicle queues at study area intersections are anticipated to get slightly longer with the addition of Amtrak Cascades service. Typically, the duration that the roads are blocked by crossing events would be similar to the duration that will be experienced once Sound Transit begins operating commuter rail service between Lakewood and downtown Tacoma. For crossings not near a station, this duration is approximately one minute or less. South of Lakewood, roads would be blocked by crossing events now from both Amtrak and freight service. Overall, the maximum queues would not increase much, and in some instances actually reduce because of signal system improvements. Exhibit 4 summarizes the maximum queues.

Exhibit 4 Conclusions from Analysis of Maximum Queues Maximum Queue Lengths Additional Intersections Blocked by Maximum Queues Approximately 2-4 vehicles longer with S. Washington Street & S. 51st Street proposed Project (PM peak hour only)

Although one additional intersection would be blocked with the proposed Project, the surrounding street grid provides opportunities for drivers to slightly adjust their routes around this queue.

Safety

The faster passenger and freight train movements at the crossings on the Bypass Route alignment resulted in the project team looking at potential safety improvements and predicting the anticipated accident frequency with the proposed Project.

Crossing Area Improvements with Potential to Improve Safety

The following improvements would improve safety and be added by the Build Alternative at several existing at-grade crossings:

 Do Not Stop On Tracks signs.

 Wayside horns to provide automated audible warnings directed towards street traffic at a rail/roadway at-grade crossing to forewarn people of an approaching train.

 Median barriers to physically inhibit vehicles attempting to go around the railroad crossing gates.

 Sidewalks for an ADA-accessible route over the tracks with tactile strips alerting sight-impaired travelers to changes ahead.

 Pre-signals to stop vehicles in front of the railroad crossings before the downstream queue begins to back up across the tracks.

 More advanced signal controllers at the N. Thorne Lane SW, Berkeley Street SW, 41st Division Drive, and Barksdale Avenue crossing areas, which would allow nearby signals to operate in synchronized fashion and lower the likelihood of vehicles being on the tracks during a crossing.

Predicted Accident Experience

Methodology

The Federal Railroad Administration (FRA) accident prediction model railroad-highway grade crossings was used to predict the number of accidents for the No Action Alternative and Build Alternative. Applying this model required the following steps to be taken:

1) Gather the most recently available five years of accident data for the railroad- highway grade crossings. This was obtained from the FRA Office of Safety Analysis web page (http://safetydata.fra.dot.gov/OfficeofSafety/) for the existing at-grade railroad crossings in the study area.

2) Input crossing characteristics. The FRA crossing inventory database provided much of this information. This information was augmented using project-specific data that was available for roadway traffic volumes at at-grade crossings for the Bypass route, and train volume forecasts for the Bypass Route and Point Defiance Route. Additionally, the crossing characteristics were adjusted for the Build Alternative where improvements affecting safety would be made.

Two accident frequency thresholds useful for considering the need for considering crossing improvement were found in the Railroad-Highway Grade Crossing Handbook published by the Federal Highway Administration. These thresholds apply regardless of whether or not the improvements are economically justifiable:

 For crossings with active devices without gates, when the expected accident frequency exceeds 0.1 accidents per year (1 accident every 10 years) as predicted by the US DOT Accident Prediction Formula, consider active devices with gates.

 For crossings with active devices with gates, when the expected accident frequency exceeds 0.5 accidents per year (1 accident every 2 years) as predicted by the US DOT Accident Prediction Formula, consider grade separation.

These thresholds were used as measures to conclude whether additional safety improvements would be needed to resolve future safety conditions. The results from using the US DOT Accident Prediction formula are in units of accidents per year. This often results in very low numbers when looking at individual crossings, which makes it more challenging for the general public to have a good understanding of the numbers. As a result, the analysts converted the predicted accident experience to the number of years between accidents rather than accidents per year.

To express the predicted accident experience in term traffic engineers more commonly use to review safety, the predicted accident experience was also converted to an exposure-based accident rate. The exposure of one million train crossings was used as the basis for the accident rate because when a train is not crossing, vehicles and nonmotorized traffic cannot collide with a train.

Year 2030 Analysis

The number of average daily train crossings and predicted annual accident frequencies were used to predict the following accidents rates per million train crossings for the overall corridor (the predicted experience on the Point Defiance Route and Bypass Route):

 With the No Action Alternative, 3.6 accidents for every million train crossings overall for both routes (the Point Defiance Route and the Bypass Route) and 7.0 accidents for every million train crossings on the Bypass Route.

 With the Build Alternative, 3.2 accidents for every million train crossings overall for both routes and 4.1 accidents for every million train crossings on the Bypass Route.

By measuring the accident rate per million train crossings, one can see how the safety improvements allowed for the Build Alternative to carry more train traffic and more safely than the No Action Alternative.

The accident frequencies for the alternatives in terms of years between accidents are shown below in Exhibit 5.

Exhibit 5 Corridor Accident Experience –Predicted for Year 2030 Conditions Change Corridor Summary Years between Accidents Build vs. No Action No Action Build Alternative Alternative Time between Route Prediction Prediction Accidents Point Defiance Route 3.2 3.3 0.1 years longer Bypass Route 1.4 1.2 0.2 years shorter Both Routes Combined 1.0 0.9 0.1 years shorter

The following factors resulted in the above accident frequencies:

 Street traffic volumes do not increase with the Build Alternative when compared to the No Action Alternative.

 With the Build Alternative, train volumes increase on the Bypass Route, but decrease on the Point Defiance Route.

 With the Build Alternative, on the Bypass Route, improvements have been included at several railroad crossings that improve safety (for example, gates).

When accidents do occur with the Build Alternative, accidents would increase in severity along the Bypass Route south of the Lakewood Sounder Station because high-speed trains do not currently travel along this segment. Overall, accidents would occur 0.1 years more frequently with the Build Alternative than with the No Action Alternative; however, there are more train crossing events and the accident rate per million train crossings improves with the Build Alternative.

When Amtrak service shifts from the Point Defiance Route, the accident frequency is predicted to improve on the Point Defiance Route at individual crossings.

On the Bypass Route, accidents would occur with the Build Alternative more frequently (0.2 years earlier) than the No Action Alternative, this is partially due to the total daily crossing events on the Bypass Route increasing by 105 percent. Despite having less time between accidents, the Build Alternative would lower the accident rate per train crossing event. The project team reviewed individual crossing accident predictions and no crossing would satisfy the threshold of one accident every other year described in the methodology section for the next level of crossing improvements (grade separation). The largest effects occur at Bridgeport Way and Barksdale Avenue, where the frequency between accidents would be shortened by 37 percent.

Exhibit 6 Greatest Effects on Individual Crossing Accident Experience–Predicted for Year 2030 Change Individual Crossings Years between Accidents Build vs. No Action No Action Build In Crossing Alternative Alternative In Train Crossing ID Prediction Prediction Years Volume Bridgeport Way SW 085821P 35 22 -13 700% Barksdale Ave 085836E 46 29 -17 700%

LESSONS LEARNED

In preparing the report, a few lessons were learned:

 Intersection LOS and delay, although typical operational measures of effectiveness used for studying project effects, may need to be augmented with other measures such as queues when project effects only affect part of the hour.

 Maximum queues are a useful means by which to measure effects of events that occur a minimal number of times per hour. Ideally, the time at which the maximum queue occurs would also be recorded. Graphics were used in the transportation discipline report to clearly report the maximum queue at each leg of the study intersections. This simplified the review for those report readers unaccustomed to reading queue tables.

 Convert units of engineering calculations to best communicate numbers to the general public as well as traffic engineers. For example, with the safety analysis, predicted accidents were reported in terms of years between accidents (a recurrence interval). To assist the traffic engineering review, predicted accident rates were also expressed in units of accidents per million train crossings.

CONCLUSION

The proposed Project would have some measurable effects on the study area, however, safety would not be compromised and effects on operations are generally balanced throughout the study area.

REFERENCES

WSDOT. 2012. Point Defiance Bypass Project Transportation Discipline Report.

US DOT. 2007. Railroad-Highway Grade Crossing Handbook – Revised Second Edition 2007. Federal Highway Administration. August 2007.

AUTHOR INFORMATION

Carter A. Danne, PE, PTOE Cell Phone: (206) 909-7044 [email protected]