Shelter

Shelter or a safe refuse from the environment is essential not just on Mars but anywhere.

Safety for living on Mars will depend on shelters as well as habitats to live.

Even moving just a short distance for the spaceship or main base station will be a very risky endeavor almost equivalent to a space walk.

A Basic shelter could consist of a pressurized area where colonists can enter to enable safe havens where spare oxygen, food and water supplies as well as being heated, with communication systems and spare Marsuits.

These shelters could also have basic medical and basic toilet facilities and sufficient energy for charging for a Marsuit in an emergency.

These shelters would need easy access for emergencies and some level of radiation protection.

Construction of such shelters and supplies could be done using robotic construction systems that build a shelter before human exploration begins in an area, ready to support an emergency if a fault was to develop in the colonist transportation.

For any distance on Mars human transportation will include all the same capabilities.

Outposts

Each outpost will need to include a more heavily shielded area underground for protection from Solar flares, this type of outpost will be required to be built to enable colonist to safely able to fully retreat to within a few hours or so.

Most flares are quite short, less than hour. The longest flare that we've seen with the Japanese Yohkoh satellite was 12 hours.

Yet there should be a 15-hour warning about the arrival of a “coronal mass ejection” to Mars

Interesting link to SPACE WEATHER PREDICTION CENTER