What factors would cause a difference in the use of financial leverage
for a utility company and an automobile company?

Risk

Utilities can assume relatively higher levels of debt in their capital
mix than an automobile manufacturer as a result of having relatively
lower business and financial risk.  Specifically, beta, the measure of
market risk for a firm will usually be lower for utilities.  Beta is a
component in calculating a firms cost of equity.  Equity and debt's
relationship to each other determines the degree of financial
leverage.

A company producing energy (regulated, allowed to earn a profit,
predictable demand)has significantly less risk than a company
producing automobiles.

Net, higher debt levels relative to equity for a utility are allowed
(and preferred by a firm due to interest deductibility) by investors
as they do not add the same perceived risk to the company

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