Side impact is one of the most dangerous types of guardrail crashes. Of particular concern is a nontracking vehicle sliding sideways into a guardrail end treatment. This study investigated the issue of end terminal-side crashes with the use of a data set of 142 guardrail crashes extracted from the National Automotive Sampling System–Crashworthiness Data System. Side crashes involving an end terminal were substantially over-represented in driver injuries. End terminal contact occurred in about 25% of all guardrail-side crashes but represented almost 70% of driver injuries. Terminals that were noncompliant with NCHRP Report 350 were roughly five times as likely as compliant designs to cause serious crash injury. Collisions with terminals were also about twice as likely to initiate rollover compared with collisions with the length-of-need section of the guardrail. When injuries caused by rollovers, unbelted drivers, and driver ejections were accounted for, the risk presented by terminal contact was accentuated, as was the difference between cars, light trucks, and vans in terminal impacts.