Class 1 Practice Results - #1. If a load is supported on rollers, how many of the rollers must be locked? one one two two three three All All If a load is supported on rollers, then lock at least one roller to prevent the load from shifting. The load must also have adequate tiedowns If a load is supported on rollers, then lock at least one roller to prevent the load from shifting. The load must also have adequate tiedowns Next