Here is an example of an all too common scenario I see my clients are involved in due to the lack of insurance coverage:

You are a service technician going on your way to a service call, driving your employer’s truck when another vehicle rear ends you at a traffic light. The person who caused the accident has liability coverage of $15,000 and your employer does not provide any underinsurance coverage on the vehicle you’re driving. The technician has an automobile policy that provides for underinsurance coverage of $25,000, but you sustain serious injuries and are out of work for six months. During this time, workers’ compensation pays $60,000 you in benefits.
Because you were injured at work, you are entitled to workers’ compensation benefits. These benefits include payment of medical bills and payment of wage loss benefits if the injuries prevent you from returning to work. However, the workers’ compensation carrier has a right to be paid back from monies available to you from the person who caused the accident. Although your employer provided workers’ compensation, they did not provide any underinsured motorist coverage for the vehicle you were driving.

In this case, you have a right to the underinsurance benefits under your policy and the workers compensation carrier does not have any right of reimbursement from these monies.
Remember: insurance coverage and applicability can be complicated issues and insurance coverage can come from multiple sources. Be sure you know what you are entitled to if you’re injured in a work-related accident.