Missouri highway officials are proposing to widen Interstate 70 to three lanes in each direction between suburban St. Louis and Kansas City if voters approve a transportation sales tax. The I-70 project between Wentzville and Independence was one of hundreds of items on a proposed project list released Fridayby the Missouri Department of Transportation. The agency plans to take public comments through July 3, and the state Highways and Transportation Commission will vote on a final list July 9. Proposed Constitutional Amendment 7 on the August ballot will ask voters whether to impose a three-quarters cent sales tax for transportation that would last for 10 years. The measure says it would raise $534 million annually for state and local governments.