the preferred lighting apparatus is illustrated in fig1 - 3 . as shown , the apparatus includes a horizontal step plate portion 13 and a vertical riser plate portion 15 . the step plate portion 13 includes a flat undersurface 17 , which typically abuts the horizontal surface of a step , while the riser plate portion 15 includes a flat vertical undersurface 19 which typically mounts against the vertical riser portion of a step . the particular embodiment shown further includes respective carpet insert slots 21 , 23 . a number of ribs 25 , 27 , 29 , 31 are formed between the inner surfaces 15 , 17 and the outer surface 33 of the apparatus , which includes a horizontal or “ tread ” portion 35 and outer riser surface 37 . as further illustrated , a rounded nose portion 38 includes a light reflective layer 39 , which forms a continuous outer surface with surfaces 35 and 37 . in the preferred embodiment , reflective layer 39 is applied by coextrusion with the remainder of the structure . in this connection , layer 39 preferably comprises a light gray polyvinyl chloride ( pvc ) strip coextruded with a black or other dark pvc material to form the entire unit 11 . the dark pvc may comprise 0 . 075 inch thick geon c9000 ( shore ) black pvc plastic , while layer 39 comprises pvc material # 291 as available from a & amp ; b plastics , yakima , wash . it has been discovered that when units 11 are disposed on each of the noses of a succession of stairs , the light gray coextruded strip reflects sufficient ambient light to alert users as to the location of the edges of the step without requiring the use of electrically activated light sources within the unit 11 . such light sources could of course still be employed , if desired . lighting apparatus according to the preferred embodiment may advantageously be used in conjunction with seat - mounted lamps 111 , as shown in fig4 . the seat - mounted lamps 111 may be so - called beacon lamps as shown in fig5 . various constructions for beacon lamps are described in pending u . s . patent application ser . no . 09 / 175 , 644 entitled seat mounted aisle step light assigned to the assignee of this application and incorporated herein by reference . the particular beacon lamp embodiment shown in fig5 includes a hemispherical lens 115 , a circular housing 113 and a lamp holder shield 117 . the particular embodiment of fig4 and 5 receives power via a feedwire 121 behind a wireway 119 . various other ways of providing power to lamps , e . g . led &# 39 ; s , located beneath the shield portion of lampholder shield 117 may be provided . an alternate and presently preferred beacon lamp 211 is illustrated in fig6 and 7 . the lamp 211 includes a hemispherical lens 215 , the upper half 216 of which is rendered opaque by suitable coating . a housing 213 has a lampshield mounting component 214 attached thereto , e . g . welding . the component 214 includes a mounting pad 216 to which a lampholder shield 217 is attached , e . g . by screws inserted through pairs of holes 220 , 222 . the lampshield 217 includes a mirrored undersurface 218 . the component 214 may be formed of bendable metal such that the pad 214 can be bent to a desired angle to adjust or aim the light pattern provided by four leds 224 mounted in the lampholder shield 217 and powered via lead wires 226 . as may be appreciated , the lampholder shield 217 directs illumination in a manner that illuminates the side of an aisleway . an illustrative lighting pattern is shown in fig8 wherein beacon lamps 211 employing four amber leds 224 are used on one side of an aisleway with 36 ″ wide steps , a 6 ″ riser and 40 ″ pitch . the decimal numbers represent light distribution in foot candles with an average of 0 . 20 foot candles . light distributions such as shown in fig8 typically will not clearly illuminate the edges of steps down the aisleway . the obscurity of the edge of the steps is particularly pronounced with led light sources because the light is monochromatic and does not produce a great deal of contrast . provision of step - mounted fixtures such as shown in fig1 - 3 provide a means of capturing and reflecting low level ambient light to provide clear demarcation of the step edges . the effect created is particularly striking and surprising to the observer . thus , in a lighting system such as shown in fig4 respective reflective layers 39 of the units 11 respond to relatively low - intensity or low - level ambient light generated by the beacon lamps 111 to render the strips 39 visible in the dark to persons traveling the staircase . from the above description , those skilled in the art will appreciate that various adaptations and modifications of the just - described preferred embodiments can be configured without departing from the scope and spirit of the invention . therefore , it is to be understood that within the scope of the appended claims , the invention may be practiced other than as specifically described herein .