General contractors, owners and public agencies commonly ask subcontractors for auto liability covering owned, hired and non-owned vehicles, usually at a $1 million combined single limit. A contractor with two trucks and no hired and non-owned coverage can fail that requirement even though its own vehicles are insured.
An umbrella or excess policy over the auto should recognize the same exposure. If the umbrella's underlying schedule reaches only owned autos, a serious crash in an employee's car may never get to it. Umbrella and excess coverage is placed separately, and it should line up with the auto policy before any certificate goes out.
Renewal is a good time to confirm all of this, and our renewal checklist includes a step for listing employees who drive their own cars. The coverage itself is explained on our hired and non-owned auto insurance page. When you're ready, get a quote that includes hired and non-owned.