Inspections
For every new type of towbar an approval number is required. To get this E4 number a prototype of every new type of towbar must be tested on a special test machine. This important test will takes 36 hours. All information during the tests is sent online directly to the head test centre of the Dutch Government of Traffic in Lelystad, where the test can be followed online. When the towbar stands the test and shows no sign of damage, the administrative settlements complete the test. After approval by the test centre mentioned above, an E4 inspection number can be issued and the production of towbars can start.