Trips commonly occur when your foot strikes an object and your momentum throws you off balance. To minimize the potential for this type of injury: 

• Do not allow carried packages to obstruct your view.
• If glasses fog due to atmospheric changes, clear them immediately.
• Use only proven walkways.
• Close desk and file drawers when not in use.
• Report burned out or missing lights.
• Be aware of elevator threshold positions
• Report any uneven or broken pavement, sidewalks, or handrails

 Falls usually take place from one level to another. One of the most common examples of this type of injury involves falling down stairs. Another involves using chairs as ladders. Preventive measures include: 

• NEVER stand on a chair to reach a high object. Always use a ladder.
• When using ladders, select the proper type and size, and use it properly. 
• Walk up and down stairs, and never jump from the last step.
• Use handrails.
• Walk.
• Report any unsafe conditions.

There is one more precautionary tip that applies in all these cases, and that is to PAY ATTENTION TO WHAT YOU ARE DOING. This is among the most common causes of injuries, and is the easiest to correct. The best walking surfaces and ideal weather conditions won’t be of any help if you are not watching where you are going.

Trip/falls are the more basic type of accident. A trip often occurs when a "change in level" of 1/2" or more occurs within a walkway (although most experts would agree that a 1/4" difference in level is sufficient to cause a person to trip. For example, the 1991 Uniform Building Code (UBC) states in Section 3304 (i):

Floor Level at Doors. Regardless of the occupant load, there shall be a floor or landing on each side of a door. When access for persons with disabilities is required by Chapter 31, the floor or landing shall not be more than 1/2 inch lower than the threshold of the doorway.

Although the UBC references doorways and not other walking surfaces, this 1/2" mandate is reinforced in the landmark 1990 Americans with Disabilities Act (ADA). The ADA utilizes two design standards, those being The Code of Federal Regulation, 24 CFR, Part 40, Accessibility Standards for Design, Construction, and Alteration of Publicly Owned Residential Structures and essentially, The American National Standard Institute (ANSI) A117.1-1986, titled, Providing Accessibility and Usability for Physically Handicapped People. This latter standard was revised and reissued as an appendix to Title III of the ADA and is titled Americans with Disabilities Act Accessibility Guidelines (ADAAG).

The ANSI 117.1-1986 Standard, Section 4.3.8 Changes in Levels, states:

If an accessible route has changes in level greater than 1/2 in (13mm), then a curb ramp, ramp, elevator, or platform lift shall be provided....

The "bottom line" is that changes in elevation of 1/2" or more are inherently dangerous and should be avoided.