NASCAR Sprint Cup driver Clint Bowyer is one of three drivers for Michael Waltrip Racing who replaced the number on the side of their car with Boston Marathon bibs Friday to honor the victims and their families in Monday's bombings.

The drivers debuted their new number schemes before practice for the STP 400 at Kansas Speedway and will use it all weekend.

Bowyer's No. 15 Marathon bib is on the side of his 5-Hour Energy Toyota.

So glad @55markmartin is putting this on his car. #NASCAR #boston twitter.com/88deevo88/stat…

— Dev (@88deevo88) April 19, 2013

Waltrip ran the Boston Marathon in 2000 and drove the No. 26 car in the Daytona 500 for Swan Racing that honored the victims in the Sandy Hook Elementary School shootings "It was a great moment of pride when they pinned the Boston Marathon bib on me," he told the Associated Press. "So it would be great to pin bib numbers on our races cars this week in Kansas."

Swan Racing will also honor the victims with a special "Prayers for Boston" paint scheme.

Prayers for Boston #nascar #NASCARstrong #PrayersForBoston twitter.com/SwanRacingCo/s…

— Swan Racing (@SwanRacingCo) April 19, 2013

Tara Davis, a Boston native and wife of Swan Racing owner Brandon Davis, said, "Boston is a strong, united community and will not be intimidated."

Driver of the No. 30 "Prayers for Boston" Toyota, David Stremme, said, "The NASCAR community rallies together in times of need. Hopefully, we can help add a little comfort with our message of 'Prayers for Boston' on the car."

Meanwhile, another part of the NASCAR family was personally affected by the loss of Sean Collier.

@daleearnold this is the hero you speak of with a friend who played ice hockey at BC twitter.com/mulassis/statu…

— Eileen Schwalm (@mulassis) April 19, 2013

Collier, 26 is the heroic MIT police officer who was killed Thursday night in Cambridge by the suspects in the Boston Marathon bombings.

Collier's brother, Andrew, is a machinist in the Hendrick Motorsports engine department. Andrew, 25, joined Hendrick Motorsports in September 2008.

Our hearts go out to the Collier family. RT @teamhendrick: Hendrick Motorsports statement: ow.ly/kejue

— Jeff Gordon (@JeffGordonWeb) April 19, 2013

"We ask that the family’s privacy be considered during this difficult time," HMS said in a statement.

Sean Collier lived in Somerville.

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