On Madison Street NW, the orange and blue markings still show where young Brenton Contee was struck by a speeding car on Saturday evening, where his rollerblade dropped off his foot, where the car ran over him.

In a city where many tragic crimes remain unsolved because frightened witnesses fail to step forth, and where there has recently been controversy over how investigations into traffic accidents have been conducted, there was an arrest in this case within 48 hours, before the marks on the pavement even faded.

"Whenever there is a kid involved, people are more likely to help," said a D.C. police spokesman in the 4th District. "In fact, the person who called to tell us where we could catch our suspect said, `I thought it was wrong no one was stepping up because what happened to that kid was horrible.' "

The caller who tipped off police about the location of the suspect was so outraged, the spokesman said, that he called police repeatedly on Monday to make sure they were pursuing the tip.

The police will not say who made the call, but in the Northwest Washington neighborhood where the hit-and-run occurred, plenty of people said they recognized the teenager behind the wheel of the car that hit the 11-year-old boy.

Yesterday, a 15-year-old who had escaped from a youth facility was arraigned in the case.

At the hearing, a magistrate found probable cause to charge the youth with assault with intent to kill while armed and driving without a permit. A third charge, assault with intent to murder while armed, was dropped, according to Walter Smith, special deputy corporation counsel.

The teenage suspect, arrested on Monday after a foot chase, has been detained at the Oak Hill facility for juveniles and faces the possibility of being tried as an adult.

"I knew before the police knew" who had been driving the car, said Brenton's brother Sean Contee, 19. "Everybody knew."

Deborah Johnson has spent every night next to her son Brenton at Children's Hospital. "I'm grateful the community came together to apprehend the driver," she said yesterday.

Brenton's condition has been upgraded from critical to serious and now to fair. With news of his improving condition, the Petworth neighborhood where his family lives seemed to sigh.

Most people said that they saw such an accident coming, that cars speed through the neighborhood at 50 or 60 mph, right through stop signs and sometimes through lights.

"We used to play double Dutch and ball in the street," said Gwendolyn Holmes, 38, who was seated on her front porch just around the corner from Brenton's house. She grew up in the house where she still lives on Eighth Street. "We used to play kickball in the alley. Now they use this street like it's a freeway."

Everyone has a story about an accident, tales of racing cars hitting fire hydrants, bouncing off curbs or hitting a stone wall on a corner. People say they keep their youngest children close, up on the porch, not even allowing them to go to the curb.

Lillie Durham puttered in her garden yesterday, snipping and digging around her petunias, gladioluses and roses. Her house faces where the car hit Brenton and carried him on the hood until he slid off. Durham ran downstairs when she heard the screaming. "It was horrible to see that little child just lying there bleeding," said Durham, 65, who raised four daughters on Madison.

At Brenton's house yesterday, his brother Sean placed another get-well card sent by a neighbor on the stereo unit so his mother could take them all to the hospital.

"They say Brenton was in a crosswalk," Sean said. "He told my mama he knew the boy and he told him to stop but he wouldn't." Sean said Brenton and the youth who was allegedly driving played basketball together sometimes.

"There were a lot of kids out skating," said Brenton's grandmother Evelyn Contee, who lives in the same house. "I bet you 30 of them ran up here to tell me what happened.

"I've sat here at this window and seen the cars fly by," said Contee, 63, an amputee who uses a wheelchair. "It's those young'ns with those old 98s and cars like that, big old cars."

Johnson was waiting to hear if Brenton's leg was broken, a minor injury compared with what she had feared. "His spirits are getting better," she said. "I'm assuring him he's not going to die and he's not going to lose his leg like his grandmother. I know how he loves to rollerblade, but I asked him if he wants to rollerblade again. He said no."

CAPTION: Deborah Johnson holds a photo of son Brenton Contee, who was hit by a car Saturday in Northwest Washington. His condition has been upgraded to fair.

CAPTION: Lillie Durham's house faces where Brenton Contee was hit by a speeding car. "It was horrible to see that little child just lying there bleeding," she said.