Does being inside a car with windows closed offer hearing protection?

What makes you think you’ve damaged your hearing? You need to be exposed to loud sounds for a good length of time to damage your hearing (ever been to a rock concert)
So noise above 75 - 85dB for a prolonged period (8 hours or more) will damage your hearing, anything over 110 - 120dB can have a immediate effect.

Glass in your car is a bit of a sound barrier, I mean it would have been a lot louder if your windows were down right, but don’t worry you won’t have damaged your hearing by this.

@hass5744 said:

What happens when an ambulance goes by.

Ambulance cab noise levels during siren use were intense (mean of 102.5 dBA in a common condition), well above the Occupational Safety and Health Administration’s suggested guidelines of 90 dBA. Hearing levels of paramedics were reduced from presbycusis expectations. In the lower and higher frequency ranges, the personnel showed hearing acuity approximately one standard deviation below the normal mean.

Source: 1980 paper, Hearing in an ambulance paramedic population - ScienceDirect1

And that’s inside the vehicle, probably with closed windows and doors. My own personal experience is that the sound in the direction of the air horn can be painfully louder. I’ve also been waiting for a light to change next to a city bus that released air from its air brakes in a big blast on starting up when the light changed and I suffered real pain and had my hearing “stunned” for a number of minutes thereafter - my driver’s side window was rolled down at the time.

In the good ol’ days, I seem to remember that fire trucks and police cars would have sirens wailing all the way to wherever they were going. These days to limit public disturbance (and perhaps to preserve hearing of all involved?), it seems like emergency vehicles only use sirens and horns as needed to clear a path, make drivers who are living in their own little world pull over, etc. And of course cops trying to catch a perpetrator in the act whiz by at high speed with lights flashing but turn off any siren in the proximity of a crime in progress to avoid giving the bad guy advance warning that the cavalry is coming.

Don’t know what you can do about a jackhammer except choose a different route. When I see any vehicle coming with flashing lights and using a siren, if it’s not a divided highway with the vehicle on the other side, I always pull over and cover my ears while waiting for the vehicle to pass.

In the UK, we call them Still Saws, very powerful and extremely loud, I have my own one, it is a Husqvarna K720, used for cutting concrete, steel, ceramic pipes, tar roads, depends on what blade/disk you have on, goes through concrete like butter with the diamond blade I use… Years ago, working on the roads, I nearly lost my dangly bits whilst cutting a drainage pipe, I never noticed the lean mix on the road was undermined, I fell backwards into the track with the still saw on full revs, luckily it landed in-between my crouch area, about an inch short of my vitals…Phew, it was a close one

Edit; Gas powered, usually 2 stroke @Raudrive