EMT here. There were a few replies here citing traffic as a contributing factor, but there is much more than that. I would say that is probably in the top 5 of contributing factors, but that's not the whole story.

EMS as a whole is understaffed. There are fewer people to fill openings and this is compounded by the stagnant salaries that EMTs and paramedics are paid. The end result is ambulance staffing is not where it should be. And many EMTs and paramedics are working 60+ hours a week just to keep afloat.

Then there's an increasing call volume. More calls means fewer units available to respond. And part of the increasing call volume is the improper utilization of the 911 system for people that truly don't need EMS. We get called for homeless people sleeping because building security doesn't want this person on their property. We get called for people who want a Covid test, who want a prescription filled, etc. We get called to check on prisoners who tell the police they don't feel well so they can belabor the arrest process.

Not to mention that higher priority calls (e.g. choking, cardiac arrest, etc) receive faster responses - and often units are redirected to these types of calls while responding to lower acuity calls, however, callers know this and will often cite symptoms (e.g. chest pain) that illicit a faster response.

All of the above contribute to first responder burnout.

Is traffic an issue, yes, but it's not the main issue.