The taper length formula for speed limits of 45 MPH or greater is defined as ______.

The taper length formula for speed limits of 45 MPH or greater is based on the principle that the taper should safely transition traffic from the current lane to allow for proper merging or diverging. The formula specifically involves calculating the width of the lane being changed and factoring in the speed of the traffic.

By multiplying the width of the lane by the speed, you create a tapered area that provides adequate space for vehicles to adjust their speed and position safely. This approach ensures that the taper is long enough to accommodate the reaction time and maneuvering space required by drivers traveling at higher speeds.

The other options do not reflect the standard practice for calculating taper length. They either suggest inappropriate methods like addition or multiplication without the correct context, making them unsuitable for determining safe traffic control taper lengths.