On-ramp is a term used to refer to the portion of a roadway that leads a driver from the entrance or access point on the highway or expressway to the main driving lanes. Other terms used synonymously for on-ramp include entrance ramp, acceleration lane, and merge lane. While the term on-ramp is the most widely used term in North America, other countries have also used different terms like slip roads, access ramps, and acceleration lanes. Regardless of the term used, on-ramps are essential for safe merging onto highways and expressways, ensuring smooth and efficient traffic flow for all motorists.