**3.3 Common wheelchair limitations**

The basic difficulties that a standard wheelchair faces involve challenges while crossing lopsided surfaces or negotiating hindrances in the pathway. Such problems may be the failure to continue any further when a wheel gets stuck in a downturn, with the end result that when the user endeavors to free oneself, the seat may get agitated and topples [7]. A comparative issue, with similar results, may happen when endeavoring to cross obstructions, for example, rocks, logs or curbs the pathway (**Figure 2**). A surface not smooth, covered with scrub and stones, may likewise be considered as uneven or unpredictable consequently imposing difficulties to mobility.

There are also cases where the user may be unable to generate enough sustained human power to climb steep grades. Thus, the conventional wheelchair has limited capability to traverse steep inclines [7]. The standard wheelchair typically uses narrow width pneumatic tires which can easily get punctured by branches, rocks and the like. When utilized in sandy, loose and unstable soil, the wheels sink and the occupant may get stuck in the process [16].

**Figure 2.** *Rock obstructions [7].*
