Deals in the dark

Severe traffic congestion during the day is forcing highway construction crews to turn increasingly to nighttime work, but the benefits of less traffic at night must be weighed against some important safety drawbacks.

The drawbacks include darkness itself—visibility is markedly poorer at night, even with lighting towers; more large trucks are on the road; with less overall traffic, motorists tend to drive faster; and there are more drowsy drivers and more alcohol-impaired and drug-impaired drivers on the road.

All these issues, and how to cope with them, were tackled during one recent session sponsored by the National Work Zone Safety Information Clearinghouse, a partnership of the American Road & Transportation Builders Association (ARTBA) and the Federal Highway Administration. The session was part of a National Traffic Management & Work Zone Safety Conference held at Fort Lauderdale, Fla., in October 2007, in conjunction with Intertraffic North America 2007 and ARTBA’s national convention.

The Fort Lauderdale overview of night work safety was led by James Bryden, a Delmar, N. Y., highway consultant and an expert in nighttime work-zone matters, whose panel included Jerry Ullman, research engineer at Texas A&M’s Texas Transportation Institute (TTI); the clearinghouse’s operating arm; Craig Ruhle, construction supervisor for the New York State Department of Transportation (NYSDOT); Julie Carter-Simon, safety manager for Ajax Paving Industries Inc., Nikonis, Fla.; and Carl Heinlein, safety consultant for American Contractors Insurance Group (ACIG), Dallas.

The panelists concluded that less roadwork during the daytime and less traffic at night probably more than offset the safety hazards that are peculiar to night work zones, so far at least. “Overall, the safety risk is lower because there is less traffic at night, but the risk per person is probably higher,” said Andy Markunis, manager of the Pennsylvania DOT’s work-zone traffic control section, in an interview.

“It’s a balance of safety, mobility and capacity. The obvious advantage of working at night is a lot more mobility,” said Bryden, the highway engineering consultant, also in an interview. He added: “The trend that is emerging is that night work done properly is as safe as or safer than work done during the day.”

David Rush, work-zone safety programs manager for the Virginia DOT (VDOT), estimated that around 35% of his state’s highway work is at night, and recently calculated that about 40% of work-zone deaths have been at night, the apparent statistical difference not being meaningful.

However, there are some signs that the nighttime low-traffic advantage may be narrowing.

Balance tipping

In a Federal Highway Administration (FHWA)-funded report, prepared by TTI and sent to Congress in July 2007, one strong indication of the impact of nighttime work on working and motoring safety can be gleaned from clues that nighttime travel is nearly three times more hazardous than daytime driving. Evidence from studies in Texas, California and elsewhere suggest that “crash rates at night increase by a higher percentage during roadwork activity (65 percent) than crash rates during day-time roadwork activities (25 percent),” the report said. Ongoing research by the Transportation Research Board should provide a more definite comparison, the study said.

Fatalities in work zones were about 43% of total work-zone deaths for a decade, National Highway Traffic Safety Administration (NHTSA) figures show, then moved up to 45% in 2003 and 2004 and to 47% in 2005 and 2006, perhaps because highway builders are shifting more work to nighttime hours every year, said TTI’s Ullman.

Overall, work-zone fatalities have been declining in recent years, but continue to hold at a fairly high level, NHTSA statistics show. That toll was 1,010 in 2006, down from 1,058 in 2005 and a high for recent years of 1,186 in 2002. Motorists—drivers and passengers—make up about 87% of the work-zone fatality total each year, with construction workers—whose work makes them especially vulnerable to these hazards—and other pedestrians accounting for the rest.

“Roadway work zones are a part of the American culture—they’re going to be around forever,” said James Baron, a spokesman for the American Traffic Safety Services Association (ATSSA), whose members sell highway equipment. He believes there is a work zone an average of about every 50 miles of U.S. highways. “Motorists need to expect the unexpected,” Baron said.

For many states, the pace of highway construction continues apace. At recent count, California’s Caltrans had 609 ongoing projects, for a record $10.7 billion. The dollar volume had risen 35% between mid-2004 and mid-2007. The Indiana DOT (INDOT) is targeting $984 million in roadwork for 2007, and “we will continue to increase construction through 2015,” under Gov. Mitch Daniels’ transportation funding plan, said Megan Tsai, an INDOT communications specialist. PennDOT awarded roughly $1.7 billion worth of highway construction contracts in 2006 and estimated it would award around $2 billion in 2007, expecting 2008 to be “on par with [last] year’s amount, if not slightly higher,” said spokesman Luke Webber.

Nationwide, $79.5 million worth of roads and bridges were put in place during 2007 by the end of September, up from $66.2 billion and $74.2 billion, respectively, in the first nine months of 2005 and 2006, ARTBA said.

Those figures put even more of a premium on minimizing travel disruptions and also on protecting motorists and workers from roadwork-related hazards. Reduced traffic during the dark hours is a safety plus, of course, and lane closures that are a necessity for roadbuilding and road repairs can be made with more flexibility and less effect on the motoring public. As a result, state transportation departments are reacting to traveler complaints that their travel is disrupted by all those construction work zones; the DOTs also are concerned about the serious safety hazards posed by a busy mix of roadwork, often involving heavy equipment, and busy motor vehicle traffic.

“The window of opportunity to do daytime work without closing lanes is getting smaller and smaller,” said VDOT’s Rush.

The Vermont DOT had half a dozen projects with considerable night work in 2007, but only two in 2006.

Most of the California DOT’s construction work is done at night, “to minimize impact on traffic during peak hours,” said spokesman David Anderson.

Carter-Simon, at Ajax Paving in Florida, estimated that 40% of her company’s work was done at night five years ago, but now that figure has risen to 60 to 70%. “Our volume of [night] work has increased steadily over the last five years,” she said.

One obvious safety problem involved with nighttime roadwork is the sharply reduced visibility that driving, or working, in the dark brings, even with artificial lights.

Who goes there?

”It’s harder for motorists to see, and it’s harder for workers to be seen,” said Bryden, the consultant. “Visibility is a big problem all around.”

Lighting must be placed facing in just the right direction to shed enough light on the paving or other work tasks. Guidelines call for a general lighting level of about 50 lumens per sq meter (lux), 100 lux for flagging, setups, paving and concrete placing and 200 lux for pavement repairing, signaling and electrical work. “You want to light the area even brighter where you’re actually doing the work,” said Ruyle of NYSDOT.

But placement of light to illuminate the work may not be adequate to illuminate the workers or traffic. “Our people need to be very well seen, and shadows really play havoc with a person’s perception,” said Carter-Simon. “At night, it’s very hard to tell how far away someone is.”

Night conditions compound the problems that drivers face in daytime work zones. These, among ones enumerated by Michael Halladay, director of the FHWA’s Office of Safety Integration, a panelist in another session of the Fort Lauderdale conference, are sudden changes in speed, changes in traffic patterns, narrower shoulders, increasing number of work zones and frustration, while the worker must cope with proximity to traffic, backovers or runovers involving construction vehicles and visibility difficulties.

“Work zones are dangerous as it is—when you insert darkness into the situation, it’s even worse,” said ATSSA’s Baron. Motorists may not see warning signs or pavement markings at night, or the signs or markings may be confusing. Or the driver may find themselves looking directly at a bright light, whose glare severely degrades visibility for driving. Drunken drivers may become disoriented by bright light and drive straight into a patrol car with flashing blue lights or into bright lights on poles, put there to improve visibility.

Drivers often tend to be more drowsy at night, especially if they’re taking advantage of lighter traffic to lengthen driving times. (Workers also may be fatigued.) With less traffic to get in their way, more drivers “take that as a signal that it’s an open road—all of a sudden, it’s giddy-up-and-go,” said Carter-Simon.

To deal with all those speeding, drunk, drug-impaired or drowsy drivers, most states are seeking to beef up police enforcement.

Blue solution

Many state DOTs hire off-duty patrol officers, paying them overtime rates. Maryland stations patrol cars in work zones, with their emergency lights flashing atop the cars, but has trouble getting enough officers to do the job. “The money is there to pay them, but they don’t have the staffing,” said Eric Tabacek, chief of the traffic development and support division of the Maryland State Highway Administration. Some officials say that having one patrol car in a zone is not enough; if the car chases a speeding motorist to give him or her a ticket, the zone is then left with no enforcement, and if it does not, drivers begin to learn that they will not be ticketed.

“Thanks to passage of a new work-zone safety law [last] spring [2007], we will now be conducting more work-zone patrols than ever before,” said INDOT’s Tsai. The law set a minimum fine for speeding in a work zone at $300, and the funds generated by work-zone arrests are used to fund more patrols in the future. The Missouri highway patrol has stepped up work-zone activity, benefiting from a statewide transportation program (2007-2011) that allocates, for the first time, funding for that activity.

A 2005 New York state law requires state patrol officers in “all major active” work zones, except New York City, which uses city police. “We try to have police presence in work zones at night,” said NYSDOT’s Ruhle. “The flashing red lights on police vehicles do more to slow down traffic than any traffic-control device.”

“We tend to use more state patrol at night than during the daylight hours,” said Frank Newboles, work-zone safety and mobility manager for the Washington State DOT (WSDOT).

“When the law enforcement is there, the speed drops,” said Heinlein of the ACIG.

For the second year, Illinois in 2007 cut the number of work-zone fatalities, to 13 in the first 10 months of 2007 from 40 in 2003, 24 in 2005 and 23 in 2006, largely by using a manned van with a camera to catch speeders.

Washington state plans a similar, limited program in spring 2008, and Maryland and Virginia also are looking at use of speed cameras. North Carolina and Vermont use “drone” cars, unmanned cars with flashing blue lights, that send out radar signals, which motorists’ radar detectors can pick up, hoping to get the drivers to slow down.

Visible guides

Whether it is from speeding, impairment or reduced visibility, drivers do not react as quickly or as well when they come upon a work zone at night. So DOTs are trying to overcome these obstacles in other ways as well. Improved lighting is one approach. “We’re always looking at those things. In my opinion, there’s no such thing as overkill when it comes to work-zone safety,” said WSDOT’s Newboles.

One approach by the DOT is new lane taping that reflects light better than painted stripes.

A number of lighting guidelines have been developed, but the main “bible” used by highway planners and builders is NCHRP Report 498, a Transportation Research Board report under the National Cooperative Highway Research Program, titled Illumination Guidelines for Nighttime Highway Work, sponsored by the American Association of State Highway & Transportation Officials, or AASHTO, and the FHWA. It recommends, for example, minimum general lighting of 54 lux and higher levels—108 lux and 216 lux—for illumination around construction equipment and precise tasks such as crack filling or moving machinery, respectively.

States including New York, New Jersey and Louisiana have turned to better lighting that reduces glare. Caltrans has increased nighttime illumination to a minimum 20-ft-diam. footprint, requires contractors to mount and direct all lighting fixtures to reduce glare for approaching traffic and has added white, retroreflective sleeves on traffic cones and barrels, which are visible from 1,000 ft at night.

In some states, including Illinois, Pennsylvania and Washington, lights that are encased in a balloon-like material diffuse the lighting, reducing glare. Otherwise, motorists could find themselves staring into a 1,000-watt light, with glare a major problem. “Many of the contractors are doing that out of their own initiative. We commend them for doing that,” said Washington state’s Newboles.

Protection Services, Harrisburg, Pa., makes what it calls a more durable “Nite Lite”—an acrylic globe that already reduces glare and which is used in 15 states.

“Most states are frowning now on traditional floodlights because of the glare in the motorist’s eyes,” said Craig Noll, vice president of sales and marketing.

Most states already are following FHWA regulations for construction workers’ light-reflective clothing, issued in late 2006, to be effective in November 2008. This “visibility rule” covers an estimated 350,000 persons who work in work zones, requiring them to wear reflective attire defined as ANSI (for American National Standards Institute) Class 2, at a minimum, recommending ANSI Class 3, which provides greater reflectivity, for flaggers. The rule applies to anyone who works within highway rights-of-way, including construction workers, police, firefighters, emergency medical service people, tow-truck operators and others.

“This is a major change. It expands the people on the road who must wear this clothing,” said Tom Flaherty, business development manager for Reflexite Americas, New Britain, Conn., which makes high-brightness prismatic sheeting. The sheeting uses prisms that reflect light better than the glass beads or microprisms that have long been used for clothing reflectivity. Many states are switching to fluorescent yellow-green vests and other clothing.

Research shows the yellow-green is more conspicuous than orange, and better distinguished from the orange or orange-and-white cones, barrels and rails used in work zones.

Fluorescent orange is still the preferred color when the background is, say, a mass of green leaves on Vermont trees.