Martin Herrera remembers too vividly the horrible night five years ago when his 18-year-old daughter, Maria, was driving too fast on Interstate 15 to react to traffic that had stopped for an accident.

“Two highway patrolmen came to our door. One of them was holding her little purse,” he says. “We saw that and just knew what happened. There weren’t many words,” but plenty of tears. “She died on impact.”

He now has a warning to help others avoid such nights:

“Slow down. I hope others who hear her story will think twice, and obey the speed limit.”

(Photo courtesy of Utah Department of Transportation) The car crash that killed Maria Herrera.

To celebrate what would have been balloon-loving Maria’s 24th birthday Thursday — and to spread a safety message — the Utah Department of Transportation displayed 90 balloons at its headquarters, one for every person who died on the state’s highways between Memorial Day and Labor Day last year.

“We call it the 100 deadliest days of the year,” said UDOT spokesman John Gleason. “Fatalities are about 50 percent higher in that period compared to the rest of the year.”

People tend to drive faster during summer months because of the good weather and good driving conditions — but it’s actually time for more vigilance.

Utah Highway Patrol Lt. Todd Royce said its troopers will be out in force this holiday weekend to encourage that.

It is adding 193 extra day shifts “to focus on aggressive speeding and distracted driving,” such as motorists talking on phones, he said.

Also, it will add 74 extra night shifts, he said, to “focus on impaired driving,” such as drunken diving.

“We hope this holiday weekend that we have zero fatalities,” Royce said. “That’s the goal.”

Herrera urges Utahns to take the warnings to heart.

“This is real,” he said. “We can lose our life in just one second when you are distracted or speeding.”

(Photo courtesy of Utah Department of Transportation) Martin and Maria Herrera before she was killed in a car crash caused by speeding.

His own loss has been devastating.

“Maria was a good girl with a bright future. She had big plans in life. She wanted to be a social worker. She wanted to do good in life,” he said. But a few moments of speeding stopped that.

“We all speed at some point, even not knowing it,” Herrera added. “We need to be more careful. It’s a way to prevent crashes.” He said raising that warning “is a way for Maria to live” — and perhaps still do good.

Besides the focus on obeying speed limits, avoiding distracted driving and preventing drunken driving, Gleason said, UDOT also is encouraging drivers to wear seat belts.

“Buckling up is the single most important thing you can do,” he said, “to save your life in a crash.”

Gleason added that studies show about 12 percent of Utahns do not wear seat belts — and they account for 50 percent of highway fatalities.

So far this year as of Thursday, 77 people have been killed on Utah highways.