Niko Triantafyllou and his brother, Angelo, know the punishment that awaits them if they disobey their mother?s rule about bicycling on Clovelly Street in Lynn.?We?re grounded,” Niko said last Thursday as he biked with his friends under Kim Triantafyllou?s watchful eye.Bicycle safety is a year-round concern for frequent cyclist and Swampscott Police Officer Brendan Reen, but it becomes one Triantafyllou?s top worries during the warm-weather months when her kids break out their bikes and race up and down Clovelly with their friends.?I give them limits on how far they can go – within eye view only,” she said.The Triantafyllous live yards away from Western Avenue, and she worries about cars using Clovelly as a shortcut from Goodridge Street to Western Avenue and speeding off of Western and down her street.?People just whip down. They do not do the speed limit,” she said.Niko Triantafyllou knows he is not supposed to ride his Mongoose bike in the street, but he occasionally swings out of his driveway in a broad loop.Reen and his brother and fellow town Officer Kevin Reen visit Swampscott schools to familiarize students with safe cycling rules and remind them of the dangers associated with cycling. During a visit to the middle school this past school year, they stressed the importance of wearing a helmet and reminded students about cycling rules that also apply to adult bicycle riders as well as motorists who share the road with cyclists.Cyclists under state law are required to stop at red lights and stop signs. Riding on sidewalks is prohibited, and riders must ride with the flow of motorized traffic.?Riders are subject to all rules of the road,” Brendan Reen said.But the law also applies to motorists who must yield to cyclists before making a turn and be observant after parking before opening a vehicle door.?The state Legislature has updated and enhanced laws for cyclists, but cyclists sometimes can be their own worst nightmare,” Reen said.He said Swampscott has its share of fitness-oriented cyclists, bike-borne commuters and “kids who ride their bikes all day long.”Niko Triantafyllou fits squarely into the last category, and his mother would like to see the city add another “caution children” sign to Clovelly.?This street is filled with bikes and scooters,” she said.Niko and his brother know their mother is watching them when they climb aboard their bikes.?She doesn?t want me to get hurt,” Niko said.