[desro]

Report from CBS News mentions the bridge handled "11.5 million" vehicles a day.

EDIT: That number seemed fishy; I think the reporter is referring to the traffic along the entire I-95 corridor.

https://x.com/CBSNews/status/1772556368106450953?s=20

[CydeWeys]

LOL, that figure is clearly off. That's double the population of the entire state!

Per another comment it's much closer to correct for the annual number of vehicle crossings.

[dgfitz]

It is between 30-35k/day, about 12.5 million/yr.

[dredmorbius]

One way to assess these numbers is to conduct a quick sanity check. How many cars per minute or second would this be?

11.5 million cars/day is equivalent to :

  ~48,000 cars/hour
   ~8,000 cars/minute
     ~130 cars/second

Clearly, somethings ... a tad off.

11.5 million cars per year however works out to:

  31,000 cars/day
   1,300 cars/hour
      21 cars/minute

Or roughly a 3 second headway per vehicle. Given four traffic lanes (two in each direction), that would be a vehicle every twelve seconds per lane, which seems far more reasonable. That's spread out over the day, so peak-hour traffic would be much higher.

Peak capacity for a highway lane is just shy 2,000 vehicles/hour:

<https://www.mikeontraffic.com/numbers-every-traffic-engineer...>

Which would put the Key Bridge's maximum capacity at about 192,000 vehicles/day.

For comparison, the San Francisco-Oakland Bay Bridge saw about 42.7 million paid toll crossings. As these are metered only in the westbound direction, actual crossings are likely double that, or 85.4 million/year, or about 230,000/day.

(The bridge sees 1/3 the total traffic of all California state-owned bridges.)

<https://mtc.ca.gov/operations/programs-projects/bridges/san-...>