accessibility standards for Federal outdoor developed areas 5 Condition for Exception 1 Compliance is not practicable due to terrain. The phrase “not practicable” means not reasonably doable. For example, where a trail is constructed in a steeply sloped area, compliance with the running slope provision may not be practicable on parts of the trail where it would require extensive cuts or fills that are difficult to construct and maintain, cause drainage and erosion problems, significantly lengthen the trail, and create other adverse environmental impacts. Condition for Exception 2 Compliance cannot be accomplished with the prevailing construction practices. This condition does not require the use of construction equipment or methods other than those typically used in a particular type of setting. For example, where handtools would normally be used to construct a trail in order to minimize the impact on a sensitive adjacent stream and the prevailing construction practices for this type of setting do not include blasting, blasting does not have to be used to remove a rock outcrop in order to comply with the clear tread width provision. Compliance with the clear tread width provision is required to the extent that it can be accomplished using handtools. Prevailing construction practices are those used by most contractors or designers faced with the same or similar projects in the area. Preferences or practices used by a single contractor or designer are not necessarily prevail- ing construction practices.