An owner of land may request that a planning board endorse a plan as not requiring approval under the subdivision control law if the plan does not show a subdivision, as that term is defined in G. L. c. 41, 81L. 9 G. L. c. 41, 81L, provides, in pertinent part "'Subdivision' shall mean the division of a tract of land into two or more lots and shall include resubdivision, and, when appropriate to the context, shall relate to the process of subdivision or the land or territory subdivided; provided, however, that the division of a tract of land into two or more lots shall not be deemed to constitute a subdivision within the meaning of the subdivision control law if, at the time when it is made, every lot within the tract so divided has frontage on: (a) a public way or a way which the clerk of the city or town certifies is maintained and used as a public way, or (b) a way shown on a plan theretofore approved and endorsed in accordance with the subdivision control law, or (c) a way in existence when the subdivision control law became effective in the city or town in which the land lies, having, in the opinion of the planning board, sufficient width, suitable grades, and adequate construction to provide for the needs of vehicular traffic in relation to the proposed use of the land abutting thereon or served thereby, and for the installation of municipal services to serve such land and the buildings erected or to be erected thereon. Such frontage shall be of at least such distance as is then required by zoning or other ordinance or by-law, if any, of said city or town for erection of a building on such lot, and if no distance is so required, such frontage shall be of at least twenty feet." In the instant case, the frontage along the existing constructed ways does not provide access to locus, by reason of the pond located in the southeastern corner of locus. of course, it is not necessary that access be available at all points along the required frontage distance. Hobbs Brook Farm Property Company v. Planning Bd. of Lincoln, 48 Mass. App. Ct. 403, 406, 721 N.E.2d 398 (2000). However, access over the unconstructed portion of a previously approved subdivision road does not suffice to support an approval not required endorsement unless there exists the assurance (by means of a bond or covenant under G. L. c. 41, 81U) that construction will be completed. Richard v. Planning Bd. of Acushnet, 10 Mass. App. Ct. 216, 219, 406 N.E.2d 728 (1980). See also Poulos v. Planning Bd. of Braintree, 413 Mass. 359, 362, 597 N.E.2d 417 (1992) (present adequate access is required). In any event, "if reasonable minds could differ on the seriousness of a problem in relation to the issuance of a special permit, it is the board's decision, and not the court's, which [is] controlling." Kinchla v. Board of Appeals of Falmouth, 11 Mass. App. Ct. 927, 415 N.E.2d 882 (1981).