Roadway Sight Distance - Expert Investigation

In this case, a Robson Forensic highway engineer was retained to investigate a two-vehicle, intersection collision to determine if highway conditions were improper in a manner that caused the collision.


This two-vehicle, intersection collision occurred on November 4, 2004, at about 10:48 p.m., in Eaton Township, Wyoming County, Pennsylvania. The collision involved:

  1. a 1997 GMC Sonoma pick-up, driven by Josh #######; and
  2. a 1993 Toyota Camry, four-door sedan, driven by LeAnn ######.

This investigation was performed to determine if highway conditions were improper in a manner that caused the collision.


The collision occurred at the intersection of Route 29 and Montross Road (Township Road 367). Route 29 is a rural highway under the jurisdiction of the Pennsylvania Department of Transportation (PaDOT). Montross Road is a local road, under the jurisdiction of Eaton Township.

According to PaDOT Traffic Volume Maps, the Average Annual Daily Traffic (AADT) on Route 29 at the crash site was 6,100 vehicles per day in 2001. The collision site is located in a rural-area of mountainous terrain where the surrounding land-use is wooded.

Route 29 is a north-south highway, running from the New York border, south of Binghamton, to the Wilkes-Barre area. Through Wyoming County, Route 29 is normally two lanes. The collision site is located at the crest of steep grades. Route 29 has auxiliary climbing lanes on both sides, and is four-lanes wide over the crest of the grades, where the intersection with Montross Road is located.

Route 29 has an asphalt surface, is divided by a concrete median, and marked with yellow edge lines at the median, broken white lane dividing lines and solid white edge lines. The edge lines and lane dividing lines are continued through the intersection. The crash occurred within Segment 211, for Route 29 southbound. Route 29 is 52 feet wide, including median.

Through the intersection, Route 29 is on a right curve and in an excavated cross section (a “cut”). The inside of the curve is an excavated embankment, which together with vegetation on the embankment limits daytime sight-distance for southbound traffic to Montross Road.

I measured the following corner sight distances:

The speed limit is the rural, unposted 55-mph. Approaching the intersection southbound is an Side Road (right) warning sign, with a 40 mph advisory speed plate, and other warning signs related to the passing zone. At the intersection Route 29 southbound is sloping down and is superelevated down to the right for the right curve.

Montross Road intersects with Route 29 on both the east and west sides; however, the intersections are not directly across from each other, and the intersection is an offset-tee. The crash occurred at West Montross, which is west of Route 29 and south of the intersection with East Montross. West Montross Road is 16 feet wide and steeply downgraded to the intersection. This road services an elder care facility at the intersection, and scattered single family homes, tying back to Route 29 south of the intersection, where Route 29 is only two-lanes wide.

Right of way through the intersection is controlled by Stop signs on Montross Road.

The collision occurred as ###### was attempting to cross Route 29 from Montross Road West, and ####### was southbound on Route 29. According to the Police Report the lighting conditions were “dark (no street lights)”, there were no adverse weather conditions but the road surface was wet.

Download the entire redacted report in the “Details” section of this page.