David A. Lieb | The Associated Press

JEFFERSON CITY, Mo. (AP) — Millions of dollars have been flowing into a Missouri campaign for a transportation sales tax from businesses and organizations that stand to benefit if voters approve the Aug. 5 ballot measure.

During the past six weeks, the campaign committee for proposed Constitutional Amendment 7 has received more than $2.3 million in large chunks ranging from $7,500 to $160,000 at a time.

Much of the money has come from highway construction contractors, who could gain hundreds of new projects worth billions of dollars over the next decade. Significant amounts also have come from labor unions that would perform the work, engineering firms that would design the projects and others whose products would be essential to the job, such as heavy equipment dealers and concrete and asphalt producers.

“To me, it shows that this is a special interest tax, and it doesn’t have grassroots support among average Missourians,” said Thomas R. Shrout, who is treasurer of a comparably low-budget campaign against the ballot measure.

The industry contributions could be considered a high-risk, high-stakes investment.

History has shown that Missouri voters are highly skeptical of tax increases. The last time a new transportation tax was on the statewide ballot, in August 2002, many of the same businesses and organizations contributed to a campaign that spent more than $3.7 million promoting the measure. Yet voters overwhelmingly defeated it by more than 72 percent. Read more