It depends where the injury occurred.
Each state and country has different rules regarding the filing of lawsuits. The time limit is called the "Statute of Limitations". Most states have a two-year Statute of Limitations, which means the lawsuit must be filed within two years of the date of injury. However, some states have only a one-year Statute of Limitations, and other states have a three year or even longer limit.
Many states also have a time period if you are going to sue a governmental agency. In highway construction, it is often the government which may be responsible for the injury. Many jurisdictions require that notice be given a certain period of time. That limit might be 30 days, 180 days, 270 days, or even two years. Failure to meet the appropriate time requirement may mean you cannot file a lawsuit for your injury.
Because of the time limits it is very important to contact an attorney as soon as possible after an injury. The attorney needs time to investigate the matter and file the lawsuit before the deadline.