Canada’s National Research Council has successfully tested a conductive concrete mix that stayed ice- and snow-free through Ottawa’s 1997 winter season. Materials scientists anticipate applications to airport runways, bridges, sidewalks, and curb ramps. Production and heating costs are reported to be modest.

ADAAG Appendix: A4.5 Ground and Floor Surfaces.
People who have difficulty walking or maintaining balance or who use crutches, canes, or walkers, and those with restricted gaits are particularly sensitive to slipping and tripping hazards. For such people, a stable and regular surface is necessary for safe walking, particularly on stairs. Wheelchairs can be propelled most easily on surfaces that are hard, stable, and regular. Soft loose surfaces, such as [...] loose sand or gravel, wet clay, and irregular surfaces such as cobblestones can significantly impede wheelchair movement.

ADAAG 4.5.4 Gratings.
If gratings are located in walking surfaces, then they should have spaces no greater than 1/2 in (13 mm) wide in one direction [...]. If gratings have elongated openings, then they shall be placed so that the long dimension is perpendicular to the dominant direction of travel.