LOS ANGELES — The downtown streets of Los Angeles these days are teeming with restaurants, music clubs, boutique hotels, sparkling new buildings and people, lots of people — swirling evidence of a transformation in a part of town that has always seemed something of an urban afterthought.

Just don’t look up. No matter how interesting city life has become out on the streets, the Los Angeles skyline remains an uninspiring procession of flattop buildings, a consequence of a 40-year-old Fire Department regulation that every skyscraper be topped by a helipad to allow for emergency rescues.

That is about to change. The Fire Department agreed last month to drop the regulation, which it had long contended was critical for public safety. In doing so, it is deferring to architects, elected officials and downtown champions who view the rule, known as Regulation 10, as superfluous at a time of advancement in fire safety technology and — worse — as a self-imposed prescription for architectural mediocrity in downtown Los Angeles at the very time that it is trying to strut its stuff for the nation.

“It’s an example of self-censorship,” said Michael K. Woo, dean of the College of Environmental Design at California State Polytechnic University, Pomona. “Architects have not been able to think about creative ways to use the tops of buildings.”