LOL The system is designed to make money, so they set them short.
The Federal Highway Administration Standard on Uniform Traffic Control Section 4D.10 Yellow Change and Red Clearance Intervals states
Standard
A yellow signal indication shall be displayed following every CIRCULAR GREEN or GREEN ARROW signal indication.
The exclusive function of the yellow change interval shall be to warn traffic of an impending change in the right-of-way assignment.
The duration of a yellow change interval shall be predetermined.
Guidance:
A yellow change interval should have a duration of approximately 3 to 6 seconds. The longer intervals should be reserved for use on approaches with higher speeds.
The Institute of Traffic Engineers have done some calculations and came up with the following:
Recommended Yellow Light Times
Three seconds should be the absolute minimum time for any intersection.
25 MPH -- 3.0 Seconds
30 MPH -- 3.5 Seconds
35 MPH -- 4.0 Seconds
40 MPH -- 4.5 Seconds
45 MPH -- 5.0 Seconds
50 MPH -- 5.5 Seconds
55 MPH -- 6.0 Seconds
