take such measures so as to ensure an equitable geographic distribution of funds, an equitable distribution of funds between urban and rural areas, and the investment in a variety of transportation modes, including public transit, passenger rail, and pedestrian improvements: Provided further , That a grant funded under this heading shall be not less than $5,000,000 and not greater than $50,000,000: Provided further , That not more than 15 percent of the funds made available under this heading may be awarded to projects in a single State: Provided further , That the Federal share of the costs for which an expenditure is made under this heading shall be, at the option of the recipient, up to 80 percent: Provided further , That the Secretary shall give priority to projects that require a contribution of Federal funds in order to complete an overall financing package: Provided further , That of the funds awarded under this heading not more than 50 percent shall be for projects located in a rural area with a population equal to or less than 200,000: Provided further , That for projects located in a rural area, the minimum grant size shall be $1,000,000 and the Secretary may increase the Federal share of costs above 80 percent: Provided further , That of the funds awarded under this heading not more than 50 percent shall be for projects located in an urbanized area with a population of more than 200,000: Provided further , That funds for an urbanized area under the previous proviso may be obligated to projects in the metropolitan area established under section 134 of title 23, United States Code, that encompasses such urbanized area: Provided further , That the Secretary shall consider the benefits of a project on urban and rural areas to the fullest extent to include all relevant geographic areas: Provided further , That projects conducted using funds provided under this heading must comply with the requirements of subchapter IV of chapter 31 of title 40, United States Code: Provided further , That the Secretary