Good work there. I worked on the Hill in a past life, so I hope nobody minds if I take the liberty of adding a few thoughts of my own.

The person you want to speak with is the Legislative Assistant (LA, in Congressional parlance) who handles transportation issues. As noted, many of these staffers are young recent graduates, but that's not a rule as some may be older and some will be experts in the field. This person should be your primary point of contact. Make sure you give them anything they ask for and be sure to get their e-mail and direct dial phone. Follow up any conversation with a "thank you for your time" email with facts and links to information on the issue. Make sure you give them your contact info in case they have questions. Be very clear exactly what you're asking the member to do.

Don't call them when Congress is in session. They're the busiest then. Congressional recesses are a great time to build relationships; the pace is slower and staffers have more time to talk.

Do a bit of homework on the Congressperson or Senator you're contacting. Knowing a bit about their legislative interests and their personal background can be helpful and it will help you to tailor your pitch to them in terms of what you choose to emphasize. As an example, a Democrat is likely to be more receptive to an appeal that mentions the possible loss of well-paid union jobs.

Ultimately, the ideal is getting a meeting with your Senator or Congressperson where you can make your pitch and ask to them directly. Don't expect more than a few minutes; they are busy people. If this is a member with a hub in their district or area, a group of 3 to 5 would be a good size for such a meeting as it's a reminder that they're dealing with a decent sized voting bloc of constituents.

Hope this helps and good luck to all working on this.