Hi
My company develops web based applications using django, a python based framework. We are based in Basingstoke, in Southern England
Reading through your specification I see the need for a eight table database (event types, customers, events, invoices, vehicle type, drivers, pickup points, dropoff points) with two web mobile interfaces Admin and Drivers.
What we will do is create what is called an API based backend, that is links into a database that will send and receive data in xml or json, then place an Angular front end on this. What this means in Non technical terms is that your interface is mobile friendly and can be removed or changed at will. It also means you can add a mobile app with ease in the future.
You have also mentioned Emails and SMS. Because of Billing issues, SMS will be problematic in North America, but emails will be no issue at all.
I would also suggest anyone who says they can build this in less than 2 weeks for less than $3000 should be treated as suspect.
My milestones are placed in such a way as you can walk away cleaning at the completion of any of them.
Marc Nealer