1. I measured the sidewalk:
   Two tile-squares of the sidewalk, are three of the construction squares, which I presume are 1 by 1m.
   https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=3532953360
   
2. Next I measured how many tiles a truck drives per minute:
   1. For that I did let the game run in normal speed, until the minute flipped.
      
   2. On which I paused the game.
      
   3. Then I took a screenshot
      
   4. I let the game run for 2 seconds (two in game minutes), until the minute flipped.
      
   5. On which I paused the game.
      
   6. Then I took another screenshot
      
   7. I counted the tiles which were 9 in both cases (+- a bit/measurement error)
      A: https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=3532978646
      B: https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=3532978863
      
      • Math:
        
      • 9 squares/2 minutes = 9*1.5m/2 minutes = 13.5 meters / 2 minutes = 6.75m/minute = 6.75m/60 seconds = 0.1125m/s (0.369094 feet/s) => 0.405 km/h (0.251678 mph)

Conclusion (also for Americans):
An average height adult walks about 1m per step, and takes 1 step per second when walking in average speed (up until about age 65 when walking speed declines).
This truck drives almost as little as ⅒ of that (I mean 125/10000 faster than ⅒, but who's counting).
It is barely outpacing a turtle at that speed* and the chance to be outpaced by a granny with a walker. That is geriatric speed! Literally!
In a city it should drive more than 100 times that fast.

Morale: Be careful with time compression when making games.

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* = 1.25 times as fast. Cudos to the Windows calculator pointing that out, while I used it to convert m/s into km/h.