POLK COUNTY, Fla. (WFLA) – Two children, aged 6 and 15, have died in crashes involving dirt bikes traveling illegally on Polk County roads in the last ten days.

Law enforcement and motorbike experts are urging people, including parents, to know which dirt bikes are safe and legal for the road.

“Brake light, tag, turn signals,” said Mike Voorhies, pointing to elements on a dirt bike designed for on and off-road use.

Voorhies, the owner of Cycle Mycle’s Motorcycle Shop in Winter Haven, says most dirt bikes belong on specialized tracks or private property, not on roads.

“When you get out in the rural areas, people are always riding around, dirt bikes, four-wheelers, on/off-road, everywhere they shouldn’t be,” he said. “Dirt bikes that are off-road only have just the bike, no lights.”

A dirt bike without lights means, in the dark, it can be impossible for others on the road to see it.

That is exactly what authorities say cost a 15-year old his life Sunday night in Lake Wales.

“It’s just a tragedy of monumental proportions,” Polk County Sheriff Grady Judd said.

According to the sheriff, the teenager was riding a dirt bike on Lewis Griffin Road near Grove Road 3 in Lake Wales at around 7:35 p.m.

He collided head-on with a 53-year old man who was riding a motorized bicycle the wrong way, the sheriff said.

“Neither one of them had headlights. Neither of them were wearing helmets and neither of them should have been on those vehicles in the road,” Sheriff Judd said.

The teenager did not survive his injuries. The motorized bicycle rider was in critical condition, as of Monday morning.

Speed does not appear to be a factor but is still under investigation, the sheriff said.

“We have one child that’s deceased and we have an adult that is clinging to life by a thread because both of them were violating the laws of the state of Florida,” said Sheriff Judd.

It came nine days after a dirt bike crash killed a 6-year old boy in Bartow.

On Feb. 4, the boy was hit and killed while walking home from school by an 18-year old on a dirt bike, according to police.

The crash occurred at approximately 3:15 pm on Summerlin Street.

“This bike was not designed or properly licensed for the roadway here in the city of Bartow,” said Bartow Police Chief Bryan Dorman.

The 18-year old suffered life-threatening injuries.

Chief Dorman says these incidents increase after the holidays when young people are given off-road vehicles as gifts.

“We need to make sure that we’re properly equipping our children with safety gear but also teaching them that these types of vehicles are not intended for the city streets,” Chief Dorman said.

It’s a message reiterated by Sheriff Judd.

“I hope that parents see this horrible tragedy that occurred to this 15-year old child and use that as an example to save some other child’s life,” Sheriff Judd said.

Both law enforcement leaders said if the other drivers survive, they could face criminal charges, in addition to civil penalties, if they are found to have been driving recklessly.