Simplify the following text for a Grade 4 native English-speaking person.
Original: The Second Severn Crossing ( Welsh : Ail Groesfan Hafren ) is a bridge over the River Severn between England and Wales . The bridge carries the M4 motorway and is one of the main routes into South Wales .
Simplified: The new crossing carries more traffic than the Severn Bridge , which is still in use .