Fall-asleep produced traumatic Chesapeake Bay Bridge crash in 2-way operations

Officials say a car driver falling asleep at the wheel and veering into the path of a truck traveling the other direction during two-way operations was the cause of the crash that sent the truck crashing down into Chesapeake Bay last Sunday morning. The car driver, a 19 year old woman, told police at the hospital and a Washington Post reporter by telephone that she fell asleep at the wheel. It was 4am.

After being hit the tractor trailer driver lost control of his direction of travel and from tire marks on the pavement of the bridge it is clear the rig headed for the bridge parapet at an angle of about 35 degrees while he attempted to brake hard. The rig punched cleanly through the concrete parapet knocking about 3m (10ft) into the Bay and moving another section outward. The driver died in the plunge of his rig into shallow waters.

The response of emergency vehicles, recovery of wreckage and temporary repairs to the broken parapet tied up traffic in delays the whole of Sunday and much of Monday. The Chesapeake Bay Bridge is the only link between the Washington-Baltimore metro area (7.6m pop) and the eastern shore and Atlantic coast.

The accident was on the older 2-lane southern span operating one lane each direction because of maintenance work that closed the 3-lane northern span. Normally the southern span carries two lanes eastbound. The 3-lane northern span normally carries three lanes westbound, or two lanes westbound and one lane eastbound.

Maryland Transportation Authority (MdTA) officials say they made the best of a difficult situation. They acknowledge that two way operations are "not ideal" but shrug off the Sunday crash as an "anomaly" and show no interest in advancing plans for building a modern span.

However two-way operations without a central barrier produced the severe hit on the truck that precipitated the Sunday crash. A central barrier or operations on separate spans would have contained the 19 year old fall asleep driver within her own direction of travel and reduced the accident to a barrier or parapet hit by the car. There might have been a crash between vehicles but a vehicle-to-vehicle crash in the one direction would have been much less severe than Sunday's head-on.

Obsolete bridge span

The 56 year old 2-lane span was built to truck weight standards of 1950 which were much less than current standards. And at the time traffic was about a tenth of current volumes.

The 2-lanes eastbound span is now a constant bottleneck because there are three travel lanes each direction on the approach highways on either side of the Bay necessitating regular contraflow or two-way operations on the newer 3-lane northern span. The two way operations occur without benefit of any central barrier to contain errant vehicles because the bridge decks of both spans are too tightly dimensioned.

65 crashes a year

There have been an average of 65 crashes a year on the bridge in the past four years, about a quarter of them, or 16 crashes per year, during two-way operations. Most are minor rear-enders under congested conditions, but a number have involved serious injury and damage. All the crashes contribute to delays and frustration to travelers.

Neither of the existing spans of the 6.9km (4.3 mile) long bridge have any breakdown shoulder or even refuges so getting emergency vehicles in, and damaged vehicles out of the way is inevitably difficult and slow.

New 3-lane span needed

The most conservative proposal is for a third span of three travel lanes south of the two lane span. This would allow eastbound travel to be accommodated without two-way operations on the northern span.

The 56-year old two-lane span could be kept in reserve for use only when maintenance is needed on the two newer three lane spans, or in emergencies such as hurricanes when greater capacity were needed. Normally the old span could be used by bikers.

Value of time saved estimates would likely show a strong willingness of motorists to pay higher tolls to avoid the delays that have become routine at the existing sub-standard bridge. The people using the bridge are among the most affluent in the world and many are traveling to beach or weekender houses - or trying to.

But amazingly for a congested and obsolete bridge a third span has never even been the subject of a feasibility study. A so-called "Needs Report" in 2004 forecast worsening congestion without new capacity, but failed to discuss alternatives and had no recommendation for action!

Maryland Transportation Authority (MdTA) that owns and operates the bridge therefore has no plan at all to improve it - a situation probably without parallel anywhere in the country.

Variable pricing

Another no-brainer for the Bay Bridge with its heavily skewed demand is to implement variable pricing to sort out those who value their trips less highly in peak times and whose travel is more optional from those who can only travel then. Higher toll rates Friday nights outbound and Sunday afternoons homebound could be used to maintain traffic flows and prevent stressful and unsafe stop-&-go.

Just 35 miles (60km) west of the Bay Bridge the USDOT's head office operates very successful value pricing and urban partnerships programs that make grants to states to fight congestion with pricing and capacity enhancement. MdTA has shown no interest, so far.

COMMENT: The lack of any leadership at MdTA on the Bay Bridge has been a longstanding problem under governors of both parties. With the latest fiasco the authority's failure to manage traffic with even minimal competence or imagination, and its refusal to produce a plan for improvement of the Bay Bridge has become politically unsustainable. If MdTA won't move to fix the problem with a new span they are likely to be told to stand aside and let someone else do the job.

Earlier report here http://tollroadsnews.com/node/3671

TOLLROADSnews 2008-08-13