Welding by the shadow. by Rob. (NYC). To run nice and straight stringers with 7018. on pipe, I use what's called  welding by the. shadow. The second pass casts a shadow. exactly at the highest part of the first. This. shadow is a perfect straight line!Just run.the puddle edge along the line formed where.NYC). To run nice and straight stringers with 7018. on pipe, I use what's called  welding by the. shadow. The second pass casts a shadow. exactly at the highest part of the first. This. shadow is a perfect straight line! Just run. the puddle edge along the line formed where.
To establish proper visual lead time on a city street, you should be looking at least 15 seconds ahead, which will work out to be at least a block ahead (about 600 feet). On the highway, you should also be looking at least fifteen seconds ahead as well, which works out to be at least one-quarter of a mile ahead.
A vehicle moving at a speed of 50 mph is slowing traffic on a two-lane highway. What passing sight distance is necessary, in order for a passing maneuver to be carried out safely? Calculate the passing sight distance by hand, and then compare it to the values recommended by AASHTO. In your calculations, assume that the following variables have the values given: Passing vehicle driver's perception/reaction time = 2.5 sec. Passing vehicle's acceleration rate = 1.47 mph/sec.