The key to safer New Haven streets may be a few new computers and a Blockwatch Web site — and community leaders are hoping that it will come at no cost to the city. New Haven is now in the running for the Byrne Memorial Competitive Grant Program from the U.S. Department of Justice. If the city wins, $129,460 would be put toward designing an interactive community policing Web site and purchasing computers for Blockwatch stations around the city. The other $12,335 would go toward overtime costs for police officers to train community members on how to use the new technology.