A backmarker is a slower car that falls one or more laps behind leaders. These vehicles usually occupy the rear of the field during a professional race. Faster cars must navigate around these slower opponents to maintain their overall track position. Officials sometimes use a blue flag to signal backmarkers to move for faster traffic. A leader lost the race because a backmarker blocked the preferred inside driving lane. Teams with smaller budgets often run as backmarkers due to limited engine performance. Maintaining a predictable racing line allows faster cars to pass these vehicles safely and quickly. Lap down cars must stay out of the way of the primary lead lap competitors.