Portland has an excellent public transportation system compared to other cities in the region. Tickets are interchangeable on buses, MAX trains and Portland streetcars - a standard pass is valid for 2.5 hours and costs $2.50USD. A day pass will cost you $5 but consider getting a 7-day pass if you're staying more than a few days; 7-day passes are only $26USD. Discounts are available and other pass options exist so check out Portland's public transportation provider, TriMet, for more information.
Portland is relatively flat, the climate is temperate, and the city calls itself Bike City, USA. This is truly a great U.S. American city to get around without a car. Buses have bike racks on the front and you can bring your bike on the MAX trains with you (if there is space). Portland even hosts a massive, naked bike ride every June to protest oil dependency and over 10,000 people showed up to pedal nude in 2014.
The beating heart of Portland's transportation network is the MAX light rail,
with 84 stations and 52 miles of connection throughout the city. MAX
trains run about every 15 minutes most of the day, every day with
less frequent service in the early morning, midday and evening.
You can buy a 2½-Hour Ticket or 1-Day Pass on the bus. Make sure you have exact amount because the operators can't make change and the farebox machines don't either. Even better, use their handy mobile ticketing app to purchase your tickets and save yourself the hassle of getting quarters. Buses are widespread and fairly punctual. TriMet also operates a robust, easy to use trip planner on their website.
In many ways Portland was a pioneer of the car-sharing movement with a local start-up that eventually became an important part of Zipcar. There are multiple options for drivers who don't want to rent a car in the traditional sense. Four taxi companies (Broadway Cab, Union Cab, Green Cab & Green Shuttle, Radio Cab Company) operate in Portland - the roughly 30 minute trip to the airport will cost an average of $35USD. Taxis wait in the center section outside of baggage claim. "Point-to-point" service is also available with Car2Go and Zipcar members accessing fleets specially marked cars parked throughout the city. Members rent them by the minute without needing to return them to the starting point and with Car2Go, parking is free. Peer-to-peer car sharing is also available through RelayRides and Getaround.