The advocacy group Transportation Alternatives says raising the cost of curbside parking would help ease congestion currently clogging city streets.The group has brought a traffic expert who says cheap parking encourages drivers to spend long periods of time looking for spaces."If you nudged up the price of curb parking until you found a couple of vacant spaces, you'd reduce traffic, you'd reduce air pollution and you'd produce a lot of money to improve the sidewalks, said Dr. Donald Shoup, a professor at UCLA.The DOT says it welcomes the suggestion. Officials say they are discussing many proposals including requiring permits on certain streets.