Two nights before Christmas in 2008, a 49-year-old Westport man walking home from a bus stop was struck and killed in a crosswalk on Post Road East. The driver of the car that hit him was never charged.

Four nights before Christmas in 2010, a 62-year-old Westport woman leaving her job at a condominium complex was struck and killed in another crosswalk on Post Road East. The driver of the car that hit her was never charged.

On the eve of Thanksgiving this year, a 19-year-old Shake Shack restaurant employee sustained a fractured pelvis when she was struck by a car as she tried to cross Post Road East after her shift ended.

In the most recent accident, it was dark, the victim was wearing dark clothing, and she was not using a crosswalk while trying to dodge heavy holiday traffic. The driver of the car that hit her was not charged. In fact, police cited the pedestrian for failing to use a crosswalk.

All three incidents bring into sharp focus the extreme danger pedestrians face trying to cross four lanes of the busiest street in Westport.

But the two fatalities in crosswalks punctuate a deadly flaw in the Post Road East infrastructure that puts the lives of pedestrians in peril each day.

When innocent people are struck and killed while obeying the rules in a crosswalk -- and the authorities cannot charge the drivers -- it points to a profound and fundamental failure of the crosswalk infrastructure itself.

It means something about the crosswalk is inherently wrong. Is it located in a place that doesn't provide approaching motorists enough visibility? Is it not illuminated adequately at night? Are pedestrian-crossing signs blocked by tree branches or other road signs?

Or is traffic typically so heavy, with four lanes of vehicles moving so fast that a dull yellow sign on the right shoulder just doesn't provide motorists adequate warning?

The two crosswalks where people were killed in 2008 and 2010 are only about 500 feet from each other. They are on a straight stretch of road populated by grocery stores, retail shops and two housing developments across the road from each other.

The two crosswalks are what traffic engineers might call "mid-block pedestrian crossings" -- meaning they are not at intersections with traffic lights. And that makes them particularly dangerous.

At crosswalks with traffic lights, the pedestrian has a fighting chance to get across a busy road in one piece. The critical element is that traffic must stop before the pedestrian "Walk" light goes on.

But the crossings where William Ford died in 2008 and Sharon Broecking was killed in 2010 don't offer the protection of red lights to stop traffic. On the nights they died, the only warnings in place for motorists at each site were a dull metal sign with a pedestrian outline on the right shoulder and the white crosswalk markings in the pavement.

Boxed in by heavy traffic at night, a motorist in the left lane might not be able to see a dark sign on the right shoulder, and unless all traffic stopped, could be on top of a pedestrian before realizing it.

There are options for these crosswalks that are far safer. And yes, they cost far more than a couple of steel signs.

After his death, Ford's sisters donated about $10,000 to the town to replace the eastbound and westbound crosswalk signs at the Sasco Creek housing development with new signs outlined in LED lights. A pedestrian using the crosswalk now can push a button, and the lights outlining the sign flash on an off.

State officials recommended the crosswalk at Westfair Road where Broecking died be removed because it is close to the improved Sasco Creek crossing. But it remains in use.

A lighted outline on a crosswalk sign is better than a dull, steel sign. But nothing commands the attention of motorists like overhead lights.

Short of installing full sets of expensive, three-color traffic lights, simpler pedestrian-activated lights are available and in use elsewhere. Single lamps on arms over the roadway flash to red when a crosswalk is in use, green when not. They provide highly visable protection.

A less costly system -- popular near some college campuses -- employs lights built into the pavement that flash when a crosswalk is in use.

Many of the pedestrians on the Post Road commute to jobs there by bus. They cross the road at least once a day -- either after getting off a bus on the way to work or to catch one home. Without structural improvements to the Post Road's mid-block crossings, the next serious accident could happen at any moment.

Yes, safety carries a price tag. What price tag do you put on a human life?