Chiang Mai:
Rót daang (red songthaew): One of the most popular ways to get around is by hopping onto a Rót daang which is a shared, open-air red truck that operates like a cross between a bus and a taxi. Routes aren’t fixed, so just flag one down and ask the driver if they’re going your way. It costs about 30 Baht for short trip and you pay when you hop off.
Some songthaew can provide taxi service (your own private ride) if you ask the driver. The fare is higher but still cheaper than a taxi (usually 150 baht or less for a one-way ride in the city). A private songthaew can also be requested by using Grab.

Other songthaew: Other than red, there are yellow, white, green and blue songthaew. Different coloured songthaew indicates different routes White songthaew goes to the east (Sankampaeng city), Blue songthaew goes to the south (Lamphun province), Yellow songthaew goes to the north (Mae Rim), and Green songthaew goes to the north-east (Mae Jo).

RTC Smart City Bus: These blue buses are an affordable and convenient way to get around in central and downtown Chiang Mai. These buses transport passengers along nine routes,]and services can be monitored in real-time via the CM Transit mobile app. There’s a flat fare of 50B baht per ride, which you can pay in cash or via the Rabbit stored-value card (get one from the RTC stand at the airport and recharge as needed at convenience stores).

White Buses: There is also local white color minibus running 2 routes in the city. The fare is only 15 baht.
Route B1 – From Arcade Bus Terminal to Chiang Mai Zoo and B2 route runs from Arcade Bus Terminal to the airport.

Tuk Tuks: Chiang Mai’ tuk-tuks (partly open cab adorned with blinking colored lights) offer transfers around town on a charter basis. Although popular with travelers, they’re more expensive than rót daang, the rate starts at 60 baht for a short trip and 100 to 150 baht for longer distance.

Bangkok:
BTS Skytrain: The BTS Skytrain is the most efficient way to get around the inner city of Bangkok. The trains run from 6am-midnight daily, and with just two lines it is easy to navigate. Most bars, restaurants, attractions and hotels in Bangkok are within a short walk of a BTS Skytrain station. Many of the city’s shopping malls have direct access to the Skytrain via a skywalk. For the BTS Skytrain, you can buy single-journey tickets from machines at each station, or purchase a Rabbit Card, which is a reusable stored-value card if you plan to use the Skytrain frequently.

MRT (Subway): Similar to the Skytrain, but underground, the MRT will connect you with most places you want to go in the city. The MRT runs from 6am-midnight. As with most cities, you should try to avoid rush hours (8-9:30am and 4-7pm) on the train systems. The MRT operates on a separate ticketing system, with single-journey tokens available at stations.

Note: Some MRT and BTS stations now also accept contactless credit or debit cards, making it easier to tap on and off without buying tickets each time. One-way fares start at 16B and go up to 59B.

Tuk Tuks: Partly open cab adorned with blinking colored lights which offers transfers around town on a charter basis. Drivers tend to open with a 100 baht bid so it's important to negotiate a price with the driver to avoid overcharging.