DENVER -- Police are stepping up their patrols for folks speeding through parks in the Denver metro area and started enforcing a 15 mph speed limit on Tuesday.

Patrol officers used radar guns to gauge a person's speed and ticketed skaters and cyclists who are breaking the speed limit. The enforcement comes as a result of an increase in accidents involving pedestrians, Denver police said.

"My understanding is that about three months ago, a child was struck by a bicyclist. I don't believe injuries occurred as a result but it was certainly brought to the attention of the parks and recreation department that this problem was ongoing," said Denver police Capt. Eric Rubin.

Some walkers and joggers complain that they have to dodge speeding cyclists when they have to cross the yellow line that separates the bike lane from the pedestrian lane.

"I've almost been clipped, way over in the middle of the walking lane by guys who are veering out across the double yellow to get around slower bicyclists," said pedestrian Gordon Rippey.

Some cyclists say that the speed limit should only apply during peak, before- and after-work hours, when the park is busy. Others think that officers should concentrate on bigger problems, such as graffiti and speeding cars, not giving $54 tickets to cruising cyclists.

"It's frustrating because ... to be clocking people on a downhill slope. I mean, I've been telling myself while going around that I'm not going any more than 15," said cyclist Jenny Killion, who was ticketed.

Some cyclists feel that pedestrians are partly to blame.

"We're being singled out as the bad guys, and there are a few of us that are bad guys, but there are a lot of other people who are bad guys too," said cyclist Gary Christlieb.

One cycling advocate said that a lack of bike lanes in the city is part of the problem.

"So many bicyclists feel that there's not a place for them on the streets so they feel forced to ride in the park, where there are no cars," said Dan Grunig, executive director of Bicycle Colorado.

He said better signage and pavement markings would help separate bicyclists and pedestrians. Most wonder if the increased enforcement will be effective. Police said they will not advertise when they will monitor the park.