Pedestrians should heed the warning to looking left, right and then left again when crossing the street this month, according to recently compiled data by Carnegie Mellon University professors.

Risk of pedestrian-vehicle collisions double between 5 and 7 p.m. in November, said David Gerard, one of the Carnegie Mellon professors who analyzed the 2005 data.

Gerard said when daylight savings time ends -- Nov. 4 this year -- the number of fatalities and risks associated with walking across streets makes a "discrete jump," which does not continue through December.

He said the risks are especially high between 6 and 7 p.m., even though the number of deaths remains relatively the same distributed over the two-hour period.

Gerard said the increase could be linked to the fact that people haven't adjusted their behavior immediately following the end of daylight savings time, which causes it to get darker sooner.

The State College Police Department just finished an analysis of four years of pedestrian-vehicle crashes in the downtown area, Lt. Dana Leonard said.

In 2006, there were two pedestrian-vehicle crashes in November and 18 for the entire year, he added.

Leonard said it makes sense that there are more accidents after the time change because people tend to travel at the same time of day despite the lack of sunlight.

However, Tyrone Parham, assistant director for university police, said the results were atypical of what is seen on campus even though there is a large volume of pedestrian activity.

"We haven't seen a November trend," he said. "There is a risk of having numerous accidents, but, surprisingly, we don't have as many pedestrian accidents as people would think."

In 2006, there was only one on-campus pedestrian-vehicle collision, with 11 accidents for the entire year, said Penn State police officer Rebecca Berdine.

Parham attributes the lack of accidents to motorists being aware of the pedestrian "culture" on campus.

"A lot of people avoid driving on campus and then those that do drive on campus, they know and they anticipate people not looking before they cross," he said.

But sometimes the pedestrians are at fault, he said.

"They know a car is there but they just expect people to stop," he said.

Leonard said it is hard to compare State College crash statistics with the national data.

"We have such small numbers," he said. "There's not a great deal of variance. You have to have larger number to run a true analysis."

On the flip side, Gerard said lives are saved during the morning hours because it is brighter.

"But, the number of lives saved in the morning doesn't offset the number of lives lost at night," he said. "It adds up to two deaths a day."

According to the Pennsylvania Department of Transportation, there were 170 pedestrian deaths and 4,569 pedestrian injuries in the commonwealth in 2006.

Unfortunately, data from future years could be skewed because of the publicity surrounding the research, Gerard said.

"The idea is that by reporting this risk, people will adjust their behavior," he said. "We've polluted it, but we'll happily claim any responsibility for any lives saved."